[PATCH v3 00/33] VKMS: Introduce multiple configFS attributes

[PATCH v3 00/33] VKMS: Introduce multiple configFS attributes

[Louis Chauvet]

VKMS have a wide range of options. The aim of this series is to introduce
many configfs attribute so VKMS can be used to test a wide range of
configurations.

PATCH 1,7,10,13,23 are to expose human readable strings from drm core
PATCH 2-4 are to expose human readable plane type in debugfs
PATCH 5,6 plane attribute
PATCH 8,9 plane rotation
PATCH 11,12 plane color encoding
PATCH 14,15 plane color range
PATCH 16,17 plane format
PATCH 18 properly use zpos
PATCH 19,20 plane zpos
PATCH 21,22 connector type
PATCH 24,25 connector supported colorspace
PATCH 26,27 connector EDID
PATCH 28,29 preparatory work for dynamic connectors
PATCH 30,31 dynamic connectors

PS: Each pair of config/configfs patch are independant. I could
technically create ≈10 different series, but there will be a lot of
(trivial) conflicts between them. I will be happy to reordoer, split and
partially apply this series to help the review process.

PS2: I will apply the patches 1..5 after my holidays, they are reviewed
twice.

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
Changes in v3:
- Added Documentation/ABI (Thomas Petazzoni)
- PATCH 2: Clarify return value
- PATCH 6,7: Avoid passing null to printf
- PATCH 7: Restrict plane name to A-Za-z0-9
- PATCH 12: Fix missing s
- PATCH 13: Add macro to avoid repetition, fix missing s, make code
  consistent, remove wrong comment, properly check bit values
- PATCH 15: Fix missing s
- PATCH 16: Fix missing s, make code consistent, remove wrong comments,
  properly check value and fix default_color_range value
- PATCH 17: Create function to reduce code complexity, fix missing s
- PATCH 18: Fix parsing, rename data, reject strings > 4 chars
- PATCH 20: Remove duplicated lines, fix test comments simplify conditions,
  remove useless documentation, 
- PATCH 21: {Min,Max}imal -> {Min,Max}imum, simplify commit log
- PATCH 25: Fix wrong comment
- PATCH 26: Rename type to colorspaces
- PATCH 27: Improve comment, avoid useless iterations
- PATCH 28: Fix typo in commit log
- PATCH 29: Fix typo in commit log
- PATCH 30: Remove useless include and move it to proper commit
- PATCH 32: Clarify documentation
- PATCH 33: Simplify code and use better variable names
- PATCH *: Fix EINVAL/EBUSY
- Link to v2: https://lore.kernel.org/r/20251029-vkms-all-config-v2-0-be20b9bf146e@bootlin.com

Changes in v2:
- PATCH 1: reorder includes (José)
- PATCH 2: use name property instead of folder name (José)
- PATCH 3: Fix default rotations (José)
- PATCH 3,5,7,12: Add tests and extract validation for planes (José)
- PATCH 3,5: Do not create color range/encoding properties if not set
- PATCH 5,6,7,8: Set plural form for vkms_config_plane fields (José)
- PATCH 4,6,8,13: Remove checking for default in supported (José)
- PATCH 9: Add break in vkms_config_plane_add_format (José)
- PATCH 12: fix zpos_enabled typo (José)
- PATCH 13: fix documentation (José)
- Add debug display (José)
- PATCH 20: use drmm_kzalloc instead of kzalloc (José)
- PATCH 22: simplify the code (José)
- Link to v1: https://lore.kernel.org/r/20251018-vkms-all-config-v1-0-a7760755d92d@bootlin.com

---
Louis Chauvet (33):
      Documentation: ABI: vkms: Add current VKMS ABI documentation
      drm/drm_mode_config: Add helper to get plane type name
      drm/vkms: Explicitly display plane type
      drm/vkms: Use enabled/disabled instead of 1/0 for debug
      drm/vkms: Explicitly display connector status
      drm/vkms: Introduce config for plane name
      drm/vkms: Introduce configfs for plane name
      drm/blend: Get a rotation name from it's bitfield
      drm/vkms: Introduce config for plane rotation
      drm/vkms: Introduce configfs for plane rotation
      drm/drm_color_mgmt: Expose drm_get_color_encoding_name
      drm/vkms: Introduce config for plane color encoding
      drm/vkms: Introduce configfs for plane color encoding
      drm/drm_color_mgmt: Expose drm_get_color_range_name
      drm/vkms: Introduce config for plane color range
      drm/vkms: Introduce configfs for plane color range
      drm/vkms: Introduce config for plane format
      drm/vkms: Introduce configfs for plane format
      drm/vkms: Properly render plane using their zpos
      drm/vkms: Introduce config for plane zpos property
      drm/vkms: Introduce configfs for plane zpos property
      drm/vkms: Introduce config for connector type
      drm/vkms: Introduce configfs for connector type
      drm/connector: Export drm_get_colorspace_name
      drm/vkms: Introduce config for connector supported colorspace
      drm/vkms: Introduce configfs for connector supported colorspace
      drm/vkms: Introduce config for connector EDID
      drm/vkms: Introduce configfs for connector EDID
      drm/vkms: Store the enabled/disabled status for connector
      drm/vkms: Rename vkms_connector_init to vkms_connector_init_static
      drm/vkms: Extract common code for connector initialization
      drm/vkms: Allow to hot-add connectors
      drm/vkms: Introduce configfs for dynamic connector creation

 Documentation/ABI/testing/configfs-vkms         | 256 +++++++
 Documentation/gpu/vkms.rst                      |  45 +-
 drivers/gpu/drm/drm_blend.c                     |  35 +-
 drivers/gpu/drm/drm_color_mgmt.c                |   4 +-
 drivers/gpu/drm/drm_connector.c                 |   1 +
 drivers/gpu/drm/drm_crtc_internal.h             |   6 -
 drivers/gpu/drm/drm_mode_config.c               |  16 +
 drivers/gpu/drm/vkms/tests/Makefile             |   3 +-
 drivers/gpu/drm/vkms/tests/vkms_config_test.c   | 244 ++++++
 drivers/gpu/drm/vkms/tests/vkms_configfs_test.c | 102 +++
 drivers/gpu/drm/vkms/vkms_config.c              | 340 ++++++++-
 drivers/gpu/drm/vkms/vkms_config.h              | 573 ++++++++++++++
 drivers/gpu/drm/vkms/vkms_configfs.c            | 953 +++++++++++++++++++++++-
 drivers/gpu/drm/vkms/vkms_configfs.h            |   6 +
 drivers/gpu/drm/vkms/vkms_connector.c           | 170 ++++-
 drivers/gpu/drm/vkms/vkms_connector.h           |  39 +-
 drivers/gpu/drm/vkms/vkms_crtc.c                |  11 +-
 drivers/gpu/drm/vkms/vkms_output.c              |  13 +-
 drivers/gpu/drm/vkms/vkms_plane.c               |  72 +-
 include/drm/drm_blend.h                         |   2 +
 include/drm/drm_color_mgmt.h                    |   3 +
 include/drm/drm_mode_config.h                   |   3 +
 22 files changed, 2796 insertions(+), 101 deletions(-)
---
base-commit: 8e7460eac786c72f48c4e04ce9be692b939428ce
change-id: 20251017-vkms-all-config-bd0c2a01846f

Best regards,
-- 
Louis Chauvet <louis.chauvet@bootlin.com>

[PATCH v3 01/33] Documentation: ABI: vkms: Add current VKMS ABI documentation

[Louis Chauvet]

VKMS recently introduced a ConfigFS API to configure new devices.
Add proper ABI documentation.

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 Documentation/ABI/testing/configfs-vkms | 118 ++++++++++++++++++++++++++++++++
 1 file changed, 118 insertions(+)

diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
new file mode 100644
index 000000000000..0beaa25f30ba
--- /dev/null
+++ b/Documentation/ABI/testing/configfs-vkms
@@ -0,0 +1,118 @@
+What:		/sys/kernel/config/vkms/
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        This group contains sub-groups corresponding to created
+		VKMS devices.
+
+What:		/sys/kernel/config/vkms/<device>
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        This group contains sub-groups corresponding to the VKMS
+        device <device>.
+
+What:		/sys/kernel/config/vkms/<device>/connectors
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        This group contains sub-groups corresponding to the
+        connectors of the VKMS device <device>.
+
+What:		/sys/kernel/config/vkms/<device>/connectors/<connector>
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        This group contains attributes corresponding to the
+        connector <connector> of the VKMS device <device>.
+
+What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/status
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        Connection status of the connector. Possible values:
+        1 - connected, 2 - disconnected, 3 - unknown.
+
+What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/possible_encoders
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        This group contains symbolic links to possible encoders
+        for this connector.
+
+What:		/sys/kernel/config/vkms/<device>/crtcs
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        This group contains sub-groups corresponding to the
+        CRTCs of the VKMS device <device>.
+
+What:		/sys/kernel/config/vkms/<device>/crtcs/<crtc>
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        This group contains attributes corresponding to the
+        CRTC <crtc> of the VKMS device <device>.
+
+What:		/sys/kernel/config/vkms/<device>/crtcs/<crtc>/writeback
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        Enable or disable writeback connector support for this
+        CRTC. Value: 1 - enabled, 0 - disabled.
+
+What:		/sys/kernel/config/vkms/<device>/encoders
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        This group contains sub-groups corresponding to the
+        encoders of the VKMS device <device>.
+
+What:		/sys/kernel/config/vkms/<device>/encoders/<encoder>
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        This group contains attributes corresponding to the
+        encoder <encoder> of the VKMS device <device>.
+
+What:		/sys/kernel/config/vkms/<device>/encoders/<encoder>/possible_crtcs
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        This group contains symbolic links to possible CRTCs
+        for this encoder.
+
+What:		/sys/kernel/config/vkms/<device>/planes
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        This group contains sub-groups corresponding to the
+        planes of the VKMS device <device>.
+
+What:		/sys/kernel/config/vkms/<device>/planes/<plane>
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        This group contains attributes corresponding to the
+        plane <plane> of the VKMS device <device>.
+
+What:		/sys/kernel/config/vkms/<device>/planes/<plane>/type
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        Plane type. Possible values: 0 - overlay, 1 - primary,
+        2 - cursor.
+
+What:		/sys/kernel/config/vkms/<device>/planes/<plane>/possible_crtcs
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        This group contains symbolic links to possible CRTCs
+        for this plane.
+
+What:		/sys/kernel/config/vkms/<device>/enabled
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        Enable or disable the VKMS device. Value: 1 - enabled,
+        0 - disabled.

-- 
2.51.2

[PATCH v3 02/33] drm/drm_mode_config: Add helper to get plane type name

[Louis Chauvet]

Create and export an helper to display plane type using the
property string. This could be used to display debug
information in VKMS.

Reviewed-by: José Expósito <jose.exposito@redhat.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/drm_mode_config.c | 16 ++++++++++++++++
 include/drm/drm_mode_config.h     |  3 +++
 2 files changed, 19 insertions(+)

diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
index d12db9b0bab8..c940a67e255b 100644
--- a/drivers/gpu/drm/drm_mode_config.c
+++ b/drivers/gpu/drm/drm_mode_config.c
@@ -231,6 +231,22 @@ static const struct drm_prop_enum_list drm_plane_type_enum_list[] = {
 	{ DRM_PLANE_TYPE_CURSOR, "Cursor" },
 };
 
+/**
+ * drm_get_plane_type_name - return a string for plane name
+ * @type: plane type to compute name of
+ *
+ * Returns: The name of the plane type. "(unknown)" if type is not a known
+ * plane type.
+ */
+const char *drm_get_plane_type_name(enum drm_plane_type type)
+{
+	if (type > 0 && type < ARRAY_SIZE(drm_plane_type_enum_list))
+		return drm_plane_type_enum_list[type].name;
+	else
+		return "(unknown)";
+}
+EXPORT_SYMBOL(drm_get_plane_type_name);
+
 static int drm_mode_create_standard_properties(struct drm_device *dev)
 {
 	struct drm_property *prop;
diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
index 895fb820dba0..f4c580fa2a52 100644
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h
@@ -30,6 +30,7 @@
 #include <linux/llist.h>
 
 #include <drm/drm_modeset_lock.h>
+#include <drm/drm_plane.h>
 
 struct drm_file;
 struct drm_device;
@@ -1001,4 +1002,6 @@ static inline int drm_mode_config_init(struct drm_device *dev)
 void drm_mode_config_reset(struct drm_device *dev);
 void drm_mode_config_cleanup(struct drm_device *dev);
 
+const char *drm_get_plane_type_name(enum drm_plane_type type);
+
 #endif

-- 
2.51.2

[PATCH v3 03/33] drm/vkms: Explicitly display plane type

[Louis Chauvet]

Debug information are mainly read by human, so use full name instead
of values.

Reviewed-by: José Expósito <jose.exposito@redhat.com>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/vkms_config.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
index 8788df9edb7c..ec0001adc4d1 100644
--- a/drivers/gpu/drm/vkms/vkms_config.c
+++ b/drivers/gpu/drm/vkms/vkms_config.c
@@ -352,8 +352,8 @@ static int vkms_config_show(struct seq_file *m, void *data)
 
 	vkms_config_for_each_plane(vkmsdev->config, plane_cfg) {
 		seq_puts(m, "plane:\n");
-		seq_printf(m, "\ttype=%d\n",
-			   vkms_config_plane_get_type(plane_cfg));
+		seq_printf(m, "\ttype=%s\n",
+			   drm_get_plane_type_name(vkms_config_plane_get_type(plane_cfg)));
 	}
 
 	vkms_config_for_each_crtc(vkmsdev->config, crtc_cfg) {

-- 
2.51.2

[PATCH v3 04/33] drm/vkms: Use enabled/disabled instead of 1/0 for debug

[Louis Chauvet]

Debug information are mainly read by human, so display human
readable values.

Reviewed-by: José Expósito <jose.exposito@redhat.com>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/vkms_config.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
index ec0001adc4d1..233e7ad4d45b 100644
--- a/drivers/gpu/drm/vkms/vkms_config.c
+++ b/drivers/gpu/drm/vkms/vkms_config.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0+
 
 #include <linux/slab.h>
+#include <linux/string_choices.h>
 
 #include <drm/drm_print.h>
 #include <drm/drm_debugfs.h>
@@ -358,8 +359,8 @@ static int vkms_config_show(struct seq_file *m, void *data)
 
 	vkms_config_for_each_crtc(vkmsdev->config, crtc_cfg) {
 		seq_puts(m, "crtc:\n");
-		seq_printf(m, "\twriteback=%d\n",
-			   vkms_config_crtc_get_writeback(crtc_cfg));
+		seq_printf(m, "\twriteback=%s\n",
+			   str_enabled_disabled(vkms_config_crtc_get_writeback(crtc_cfg)));
 	}
 
 	vkms_config_for_each_encoder(vkmsdev->config, encoder_cfg)

-- 
2.51.2

[PATCH v3 05/33] drm/vkms: Explicitly display connector status

[Louis Chauvet]

Debug information are mainly read by human, so use full name instead
of raw values for connector status.

Reviewed-by: José Expósito <jose.exposito@redhat.com>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/vkms_config.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
index 233e7ad4d45b..ed1cd8d153c5 100644
--- a/drivers/gpu/drm/vkms/vkms_config.c
+++ b/drivers/gpu/drm/vkms/vkms_config.c
@@ -3,6 +3,7 @@
 #include <linux/slab.h>
 #include <linux/string_choices.h>
 
+#include <drm/drm_connector.h>
 #include <drm/drm_print.h>
 #include <drm/drm_debugfs.h>
 #include <kunit/visibility.h>
@@ -368,8 +369,8 @@ static int vkms_config_show(struct seq_file *m, void *data)
 
 	vkms_config_for_each_connector(vkmsdev->config, connector_cfg) {
 		seq_puts(m, "connector:\n");
-		seq_printf(m, "\tstatus=%d\n",
-			   vkms_config_connector_get_status(connector_cfg));
+		seq_printf(m, "\tstatus=%s\n",
+			   drm_get_connector_status_name(vkms_config_connector_get_status(connector_cfg)));
 	}
 
 	return 0;

-- 
2.51.2

[PATCH v3 06/33] drm/vkms: Introduce config for plane name

[Louis Chauvet]

As planes can have a name in DRM, prepare VKMS to configure it using
ConfigFS.

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/vkms_config.c |  5 +++++
 drivers/gpu/drm/vkms/vkms_config.h | 26 ++++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_plane.c  |  3 ++-
 3 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
index ed1cd8d153c5..f31a1eb8f811 100644
--- a/drivers/gpu/drm/vkms/vkms_config.c
+++ b/drivers/gpu/drm/vkms/vkms_config.c
@@ -356,6 +356,9 @@ static int vkms_config_show(struct seq_file *m, void *data)
 		seq_puts(m, "plane:\n");
 		seq_printf(m, "\ttype=%s\n",
 			   drm_get_plane_type_name(vkms_config_plane_get_type(plane_cfg)));
+		seq_printf(m, "\tname=%s\n",
+			   vkms_config_plane_get_name(plane_cfg) ?
+			   vkms_config_plane_get_name(plane_cfg) : "(null)");
 	}
 
 	vkms_config_for_each_crtc(vkmsdev->config, crtc_cfg) {
@@ -397,6 +400,7 @@ struct vkms_config_plane *vkms_config_create_plane(struct vkms_config *config)
 	plane_cfg->config = config;
 	plane_cfg->default_pipeline = false;
 	vkms_config_plane_set_type(plane_cfg, DRM_PLANE_TYPE_OVERLAY);
+	vkms_config_plane_set_name(plane_cfg, NULL);
 	xa_init_flags(&plane_cfg->possible_crtcs, XA_FLAGS_ALLOC);
 
 	list_add_tail(&plane_cfg->link, &config->planes);
@@ -409,6 +413,7 @@ void vkms_config_destroy_plane(struct vkms_config_plane *plane_cfg)
 {
 	xa_destroy(&plane_cfg->possible_crtcs);
 	list_del(&plane_cfg->link);
+	kfree_const(plane_cfg->name);
 	kfree(plane_cfg);
 }
 EXPORT_SYMBOL_IF_KUNIT(vkms_config_destroy_plane);
diff --git a/drivers/gpu/drm/vkms/vkms_config.h b/drivers/gpu/drm/vkms/vkms_config.h
index 8f7f286a4bdd..b9a41a22c011 100644
--- a/drivers/gpu/drm/vkms/vkms_config.h
+++ b/drivers/gpu/drm/vkms/vkms_config.h
@@ -35,6 +35,7 @@ struct vkms_config {
  *
  * @link: Link to the others planes in vkms_config
  * @config: The vkms_config this plane belongs to
+ * @name: Name of the plane
  * @type: Type of the plane. The creator of configuration needs to ensures that
  *        at least one primary plane is present.
  * @possible_crtcs: Array of CRTCs that can be used with this plane
@@ -47,6 +48,7 @@ struct vkms_config_plane {
 	struct list_head link;
 	struct vkms_config *config;
 
+	const char *name;
 	enum drm_plane_type type;
 	struct xarray possible_crtcs;
 	bool default_pipeline;
@@ -314,6 +316,30 @@ vkms_config_plane_set_default_pipeline(struct vkms_config_plane *plane_cfg,
 	plane_cfg->default_pipeline = default_pipeline;
 }
 
+/**
+ * vkms_config_plane_set_name() - Set the plane name
+ * @plane_cfg: Plane to set the name to
+ * @name: New plane name. The name is copied.
+ */
+static inline void
+vkms_config_plane_set_name(struct vkms_config_plane *plane_cfg,
+			   const char *name)
+{
+	if (plane_cfg->name)
+		kfree_const(plane_cfg->name);
+	plane_cfg->name = kstrdup_const(name, GFP_KERNEL);
+}
+
+/**
+ * vkms_config_plane_get_name - Get the plane name
+ * @plane_cfg: Plane to get the name from
+ */
+static inline const char *
+vkms_config_plane_get_name(const struct vkms_config_plane *plane_cfg)
+{
+	return plane_cfg->name;
+}
+
 /**
  * vkms_config_plane_attach_crtc - Attach a plane to a CRTC
  * @plane_cfg: Plane to attach
diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
index 19fe6acad306..d8612e28ac3f 100644
--- a/drivers/gpu/drm/vkms/vkms_plane.c
+++ b/drivers/gpu/drm/vkms/vkms_plane.c
@@ -11,6 +11,7 @@
 #include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drm_print.h>
 
+#include "vkms_config.h"
 #include "vkms_drv.h"
 #include "vkms_formats.h"
 
@@ -228,7 +229,7 @@ struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev,
 					   &vkms_plane_funcs,
 					   vkms_formats, ARRAY_SIZE(vkms_formats),
 					   NULL, vkms_config_plane_get_type(plane_cfg),
-					   NULL);
+					   vkms_config_plane_get_name(plane_cfg));
 	if (IS_ERR(plane))
 		return plane;
 

-- 
2.51.2

[PATCH v3 07/33] drm/vkms: Introduce configfs for plane name

[Louis Chauvet]

Planes can have name, create a plane attribute to configure it. Currently
plane name is mainly used in logs.

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 Documentation/ABI/testing/configfs-vkms |  6 +++++
 Documentation/gpu/vkms.rst              |  3 ++-
 drivers/gpu/drm/vkms/vkms_configfs.c    | 43 +++++++++++++++++++++++++++++++++
 3 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
index 0beaa25f30ba..6fe375d1636f 100644
--- a/Documentation/ABI/testing/configfs-vkms
+++ b/Documentation/ABI/testing/configfs-vkms
@@ -103,6 +103,12 @@ Description:
         Plane type. Possible values: 0 - overlay, 1 - primary,
         2 - cursor.
 
+What:		/sys/kernel/config/vkms/<device>/planes/<plane>/name
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        Name of the plane.
+
 What:		/sys/kernel/config/vkms/<device>/planes/<plane>/possible_crtcs
 Date:		Nov 2025
 Contact:	dri-devel@lists.freedesktop.org
diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index 1e79e62a6bc4..79f1185d8645 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -87,10 +87,11 @@ Start by creating one or more planes::
 
   sudo mkdir /config/vkms/my-vkms/planes/plane0
 
-Planes have 1 configurable attribute:
+Planes have 2 configurable attributes:
 
 - type: Plane type: 0 overlay, 1 primary, 2 cursor (same values as those
   exposed by the "type" property of a plane)
+- name: Name of the plane. Allowed characters are [A-Za-z1-9_-]
 
 Continue by creating one or more CRTCs::
 
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index 506666e21c91..989788042191 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -324,10 +324,53 @@ static ssize_t plane_type_store(struct config_item *item, const char *page,
 	return (ssize_t)count;
 }
 
+static ssize_t plane_name_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_plane *plane;
+	const char *name;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+
+	scoped_guard(mutex, &plane->dev->lock)
+		name = vkms_config_plane_get_name(plane->config);
+
+	if (name)
+		return sprintf(page, "%s\n", name);
+	return sprintf(page, "\n");
+}
+
+static ssize_t plane_name_store(struct config_item *item, const char *page,
+				size_t count)
+{
+	struct vkms_configfs_plane *plane;
+	size_t str_len;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+
+	// strspn is not lenght-protected, ensure that page is a null-terminated string.
+	str_len = strnlen(page, count);
+	if (str_len >= count)
+		return -EINVAL;
+
+	if (strspn(page, "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_-") != count - 1)
+		return -EINVAL;
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		if (plane->dev->enabled)
+			return -EBUSY;
+
+		vkms_config_plane_set_name(plane->config, page);
+	}
+
+	return (ssize_t)count;
+}
+
 CONFIGFS_ATTR(plane_, type);
+CONFIGFS_ATTR(plane_, name);
 
 static struct configfs_attribute *plane_item_attrs[] = {
 	&plane_attr_type,
+	&plane_attr_name,
 	NULL,
 };
 

-- 
2.51.2

[PATCH v3 08/33] drm/blend: Get a rotation name from it's bitfield

[Louis Chauvet]

Having the rotation/reflection name from its value can be useful for
debugging purpose. Extract the rotation property table and implement
drm_get_rotation_name.

Reviewed-by: José Expósito <jose.exposito@redhat.com>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/drm_blend.c | 35 ++++++++++++++++++++++++++---------
 include/drm/drm_blend.h     |  2 ++
 2 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/drm_blend.c b/drivers/gpu/drm/drm_blend.c
index 6852d73c931c..bc7c05e20242 100644
--- a/drivers/gpu/drm/drm_blend.c
+++ b/drivers/gpu/drm/drm_blend.c
@@ -241,6 +241,31 @@ int drm_plane_create_alpha_property(struct drm_plane *plane)
 }
 EXPORT_SYMBOL(drm_plane_create_alpha_property);
 
+static const struct drm_prop_enum_list rotation_props[] = {
+	{ __builtin_ffs(DRM_MODE_ROTATE_0) - 1,   "rotate-0" },
+	{ __builtin_ffs(DRM_MODE_ROTATE_90) - 1,  "rotate-90" },
+	{ __builtin_ffs(DRM_MODE_ROTATE_180) - 1, "rotate-180" },
+	{ __builtin_ffs(DRM_MODE_ROTATE_270) - 1, "rotate-270" },
+	{ __builtin_ffs(DRM_MODE_REFLECT_X) - 1,  "reflect-x" },
+	{ __builtin_ffs(DRM_MODE_REFLECT_Y) - 1,  "reflect-y" },
+};
+
+/**
+ * drm_get_rotation_name - Return the name of a rotation
+ * @rotation: The rotation mask (DRM_MODE_ROTATE_* | DRM_MODE_REFLECT_*)
+ *
+ * Returns: the name of the rotation type (unknown) if rotation is not
+ * a known rotation/reflection
+ */
+const char *drm_get_rotation_name(unsigned int rotation)
+{
+	if (rotation < ARRAY_SIZE(rotation_props))
+		return rotation_props[rotation].name;
+
+	return "(unknown)";
+}
+EXPORT_SYMBOL(drm_get_rotation_name);
+
 /**
  * drm_plane_create_rotation_property - create a new rotation property
  * @plane: drm plane
@@ -279,14 +304,6 @@ int drm_plane_create_rotation_property(struct drm_plane *plane,
 				       unsigned int rotation,
 				       unsigned int supported_rotations)
 {
-	static const struct drm_prop_enum_list props[] = {
-		{ __builtin_ffs(DRM_MODE_ROTATE_0) - 1,   "rotate-0" },
-		{ __builtin_ffs(DRM_MODE_ROTATE_90) - 1,  "rotate-90" },
-		{ __builtin_ffs(DRM_MODE_ROTATE_180) - 1, "rotate-180" },
-		{ __builtin_ffs(DRM_MODE_ROTATE_270) - 1, "rotate-270" },
-		{ __builtin_ffs(DRM_MODE_REFLECT_X) - 1,  "reflect-x" },
-		{ __builtin_ffs(DRM_MODE_REFLECT_Y) - 1,  "reflect-y" },
-	};
 	struct drm_property *prop;
 
 	WARN_ON((supported_rotations & DRM_MODE_ROTATE_MASK) == 0);
@@ -294,7 +311,7 @@ int drm_plane_create_rotation_property(struct drm_plane *plane,
 	WARN_ON(rotation & ~supported_rotations);
 
 	prop = drm_property_create_bitmask(plane->dev, 0, "rotation",
-					   props, ARRAY_SIZE(props),
+					   rotation_props, ARRAY_SIZE(rotation_props),
 					   supported_rotations);
 	if (!prop)
 		return -ENOMEM;
diff --git a/include/drm/drm_blend.h b/include/drm/drm_blend.h
index 88bdfec3bd88..381d1f8d815b 100644
--- a/include/drm/drm_blend.h
+++ b/include/drm/drm_blend.h
@@ -42,6 +42,8 @@ static inline bool drm_rotation_90_or_270(unsigned int rotation)
 
 #define DRM_BLEND_ALPHA_OPAQUE		0xffff
 
+const char *drm_get_rotation_name(unsigned int rotation);
+
 int drm_plane_create_alpha_property(struct drm_plane *plane);
 int drm_plane_create_rotation_property(struct drm_plane *plane,
 				       unsigned int rotation,

-- 
2.51.2

[PATCH v3 09/33] drm/vkms: Introduce config for plane rotation

[Louis Chauvet]

VKMS driver supports all the rotation on planes, but for testing it can be
useful to only advertise few of them. This new configuration interface
will allow configuring the rotation per planes.

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/tests/vkms_config_test.c | 46 +++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_config.c            | 63 +++++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_config.h            | 59 +++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_plane.c             |  5 ++-
 4 files changed, 171 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/vkms/tests/vkms_config_test.c b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
index 1e4ea1863420..c33fe737678f 100644
--- a/drivers/gpu/drm/vkms/tests/vkms_config_test.c
+++ b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0+
 
+#include <drm/drm_mode.h>
 #include <kunit/test.h>
 
 #include "../vkms_config.h"
@@ -185,6 +186,12 @@ static void vkms_config_test_default_config(struct kunit *test)
 			n_possible_crtcs++;
 		}
 		KUNIT_EXPECT_EQ(test, n_possible_crtcs, 1);
+		KUNIT_EXPECT_EQ(test,
+				vkms_config_plane_get_supported_rotations(plane_cfg),
+				DRM_MODE_ROTATE_MASK | DRM_MODE_REFLECT_MASK);
+		KUNIT_EXPECT_EQ(test,
+				vkms_config_plane_get_default_rotation(plane_cfg),
+				DRM_MODE_ROTATE_0);
 	}
 
 	/* Encoders */
@@ -481,6 +488,44 @@ static void vkms_config_test_valid_plane_type(struct kunit *test)
 	vkms_config_destroy(config);
 }
 
+static void vkms_config_test_valid_plane_rotations(struct kunit *test)
+{
+	struct vkms_config *config;
+	struct vkms_config_plane *plane_cfg;
+
+	config = vkms_config_default_create(false, false, false, false);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, config);
+
+	plane_cfg = get_first_plane(config);
+
+	/* Valid, no rotation, no reflection */
+	vkms_config_plane_set_supported_rotations(plane_cfg, DRM_MODE_ROTATE_0);
+	vkms_config_plane_set_default_rotation(plane_cfg, DRM_MODE_ROTATE_0);
+	KUNIT_EXPECT_TRUE(test, vkms_config_valid_plane_rotation(config, plane_cfg));
+	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
+
+	/* Invalid, default rotation is not supported */
+	vkms_config_plane_set_supported_rotations(plane_cfg, DRM_MODE_ROTATE_0);
+	vkms_config_plane_set_default_rotation(plane_cfg, DRM_MODE_ROTATE_90);
+	KUNIT_EXPECT_FALSE(test, vkms_config_valid_plane_rotation(config, plane_cfg));
+	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
+
+	/* Invalid, supported rotations must contains at least one rotation */
+	vkms_config_plane_set_supported_rotations(plane_cfg, DRM_MODE_REFLECT_MASK);
+	vkms_config_plane_set_default_rotation(plane_cfg, DRM_MODE_REFLECT_X | DRM_MODE_ROTATE_0);
+	KUNIT_EXPECT_FALSE(test, vkms_config_valid_plane_rotation(config, plane_cfg));
+	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
+
+	/* Invalid, default rotation must contains at least one rotation */
+	vkms_config_plane_set_supported_rotations(plane_cfg,
+						  DRM_MODE_REFLECT_MASK | DRM_MODE_ROTATE_0);
+	vkms_config_plane_set_default_rotation(plane_cfg, DRM_MODE_REFLECT_X);
+	KUNIT_EXPECT_FALSE(test, vkms_config_valid_plane_rotation(config, plane_cfg));
+	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
+
+	vkms_config_destroy(config);
+}
+
 static void vkms_config_test_valid_plane_possible_crtcs(struct kunit *test)
 {
 	struct vkms_config *config;
@@ -1003,6 +1048,7 @@ static struct kunit_case vkms_config_test_cases[] = {
 	KUNIT_CASE(vkms_config_test_get_connectors),
 	KUNIT_CASE(vkms_config_test_invalid_plane_number),
 	KUNIT_CASE(vkms_config_test_valid_plane_type),
+	KUNIT_CASE(vkms_config_test_valid_plane_rotations),
 	KUNIT_CASE(vkms_config_test_valid_plane_possible_crtcs),
 	KUNIT_CASE(vkms_config_test_invalid_crtc_number),
 	KUNIT_CASE(vkms_config_test_invalid_encoder_number),
diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
index f31a1eb8f811..7aa087602807 100644
--- a/drivers/gpu/drm/vkms/vkms_config.c
+++ b/drivers/gpu/drm/vkms/vkms_config.c
@@ -3,7 +3,9 @@
 #include <linux/slab.h>
 #include <linux/string_choices.h>
 
+#include <drm/drm_blend.h>
 #include <drm/drm_connector.h>
+#include <drm/drm_mode.h>
 #include <drm/drm_print.h>
 #include <drm/drm_debugfs.h>
 #include <kunit/visibility.h>
@@ -150,6 +152,33 @@ static bool valid_plane_number(const struct vkms_config *config)
 	return true;
 }
 
+VISIBLE_IF_KUNIT
+bool vkms_config_valid_plane_rotation(const struct vkms_config *config,
+				      const struct vkms_config_plane *plane_cfg)
+{
+	struct drm_device *dev = config->dev ? &config->dev->drm : NULL;
+
+	if ((vkms_config_plane_get_default_rotation(plane_cfg) &
+	     vkms_config_plane_get_supported_rotations(plane_cfg)) !=
+	    vkms_config_plane_get_default_rotation(plane_cfg)) {
+		drm_info(dev, "Configured default rotation is not supported by the plane\n");
+		return false;
+	}
+
+	if ((vkms_config_plane_get_default_rotation(plane_cfg) & DRM_MODE_ROTATE_MASK) == 0) {
+		drm_info(dev, "Configured default rotation must contains at least one possible rotation\n");
+		return false;
+	}
+
+	if ((vkms_config_plane_get_supported_rotations(plane_cfg) & DRM_MODE_ROTATE_MASK) == 0) {
+		drm_info(dev, "Configured supported rotations must contains at least one possible rotation\n");
+		return false;
+	}
+
+	return true;
+}
+EXPORT_SYMBOL_IF_KUNIT(vkms_config_valid_plane_rotation);
+
 static bool valid_planes_for_crtc(const struct vkms_config *config,
 				  struct vkms_config_crtc *crtc_cfg)
 {
@@ -307,6 +336,12 @@ static bool valid_connector_possible_encoders(const struct vkms_config *config)
 bool vkms_config_is_valid(const struct vkms_config *config)
 {
 	struct vkms_config_crtc *crtc_cfg;
+	struct vkms_config_plane *plane_cfg;
+
+	vkms_config_for_each_plane(config, plane_cfg) {
+		if (!vkms_config_valid_plane_rotation(config, plane_cfg))
+			return false;
+	}
 
 	if (!valid_plane_number(config))
 		return false;
@@ -338,6 +373,22 @@ bool vkms_config_is_valid(const struct vkms_config *config)
 }
 EXPORT_SYMBOL_IF_KUNIT(vkms_config_is_valid);
 
+static void show_bitfield(struct seq_file *m, uint32_t value, const char *callback(unsigned int))
+{
+	u32 offset = 0;
+	bool first = true;
+
+	while (value >= BIT(offset) && offset < 32) {
+		if (value & BIT(offset)) {
+			if (!first)
+				seq_puts(m, ",");
+			seq_printf(m, callback(offset));
+			first = false;
+		}
+		offset += 1;
+	}
+}
+
 static int vkms_config_show(struct seq_file *m, void *data)
 {
 	struct drm_debugfs_entry *entry = m->private;
@@ -359,6 +410,14 @@ static int vkms_config_show(struct seq_file *m, void *data)
 		seq_printf(m, "\tname=%s\n",
 			   vkms_config_plane_get_name(plane_cfg) ?
 			   vkms_config_plane_get_name(plane_cfg) : "(null)");
+		seq_puts(m, "\tsupported rotations=");
+		show_bitfield(m, vkms_config_plane_get_supported_rotations(plane_cfg),
+			      drm_get_rotation_name);
+		seq_puts(m, "\n");
+		seq_puts(m, "\tdefault rotation=");
+		show_bitfield(m, vkms_config_plane_get_default_rotation(plane_cfg),
+			      drm_get_rotation_name);
+		seq_puts(m, "\n");
 	}
 
 	vkms_config_for_each_crtc(vkmsdev->config, crtc_cfg) {
@@ -401,6 +460,10 @@ struct vkms_config_plane *vkms_config_create_plane(struct vkms_config *config)
 	plane_cfg->default_pipeline = false;
 	vkms_config_plane_set_type(plane_cfg, DRM_PLANE_TYPE_OVERLAY);
 	vkms_config_plane_set_name(plane_cfg, NULL);
+	vkms_config_plane_set_supported_rotations(plane_cfg,
+						  DRM_MODE_ROTATE_MASK | DRM_MODE_REFLECT_MASK);
+	vkms_config_plane_set_default_rotation(plane_cfg, DRM_MODE_ROTATE_0);
+
 	xa_init_flags(&plane_cfg->possible_crtcs, XA_FLAGS_ALLOC);
 
 	list_add_tail(&plane_cfg->link, &config->planes);
diff --git a/drivers/gpu/drm/vkms/vkms_config.h b/drivers/gpu/drm/vkms/vkms_config.h
index b9a41a22c011..cf29976ec1a9 100644
--- a/drivers/gpu/drm/vkms/vkms_config.h
+++ b/drivers/gpu/drm/vkms/vkms_config.h
@@ -39,6 +39,8 @@ struct vkms_config {
  * @type: Type of the plane. The creator of configuration needs to ensures that
  *        at least one primary plane is present.
  * @possible_crtcs: Array of CRTCs that can be used with this plane
+ * @default_rotation: Default rotation that should be used by this plane
+ * @supported_rotation: Rotation that this plane will support
  * @plane: Internal usage. This pointer should never be considered as valid.
  *         It can be used to store a temporary reference to a VKMS plane during
  *         device creation. This pointer is not managed by the configuration and
@@ -50,6 +52,8 @@ struct vkms_config_plane {
 
 	const char *name;
 	enum drm_plane_type type;
+	unsigned int default_rotation;
+	unsigned int supported_rotations;
 	struct xarray possible_crtcs;
 	bool default_pipeline;
 
@@ -316,6 +320,61 @@ vkms_config_plane_set_default_pipeline(struct vkms_config_plane *plane_cfg,
 	plane_cfg->default_pipeline = default_pipeline;
 }
 
+/**
+ * vkms_config_plane_get_default_rotation() - Get the default rotation for a plane
+ * @plane_cfg: Plane to get the default rotation from
+ *
+ * Returns:
+ * The default rotation for the plane.
+ */
+static inline unsigned int
+vkms_config_plane_get_default_rotation(const struct vkms_config_plane *plane_cfg)
+{
+	return plane_cfg->default_rotation;
+}
+
+/**
+ * vkms_config_plane_set_default_rotation() - Set the default rotation for a plane
+ * @plane_cfg: Plane to set the default rotation to
+ * @default_rotation: New default rotation for the plane
+ */
+static inline void
+vkms_config_plane_set_default_rotation(struct vkms_config_plane *plane_cfg,
+				       unsigned int default_rotation)
+{
+	plane_cfg->default_rotation = default_rotation;
+}
+
+/**
+ * vkms_config_plane_get_supported_rotations() - Get the supported rotations for a plane
+ * @plane_cfg: Plane to get the supported rotations from
+ *
+ * Returns:
+ * The supported rotations for the plane.
+ */
+static inline unsigned int
+vkms_config_plane_get_supported_rotations(const struct vkms_config_plane *plane_cfg)
+{
+	return plane_cfg->supported_rotations;
+}
+
+/**
+ * vkms_config_plane_set_supported_rotations() - Set the supported rotations for a plane
+ * @plane_cfg: Plane to set the supported rotations to
+ * @supported_rotations: New supported rotations for the plane
+ */
+static inline void
+vkms_config_plane_set_supported_rotations(struct vkms_config_plane *plane_cfg,
+					  unsigned int supported_rotations)
+{
+	plane_cfg->supported_rotations = supported_rotations;
+}
+
+#if IS_ENABLED(CONFIG_KUNIT)
+bool vkms_config_valid_plane_rotation(const struct vkms_config *config,
+				      const struct vkms_config_plane *plane_cfg);
+#endif
+
 /**
  * vkms_config_plane_set_name() - Set the plane name
  * @plane_cfg: Plane to set the name to
diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
index d8612e28ac3f..7c604cfd6a09 100644
--- a/drivers/gpu/drm/vkms/vkms_plane.c
+++ b/drivers/gpu/drm/vkms/vkms_plane.c
@@ -235,8 +235,9 @@ struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev,
 
 	drm_plane_helper_add(&plane->base, &vkms_plane_helper_funcs);
 
-	drm_plane_create_rotation_property(&plane->base, DRM_MODE_ROTATE_0,
-					   DRM_MODE_ROTATE_MASK | DRM_MODE_REFLECT_MASK);
+	drm_plane_create_rotation_property(&plane->base,
+					   vkms_config_plane_get_default_rotation(plane_cfg),
+					   vkms_config_plane_get_supported_rotations(plane_cfg));
 
 	drm_plane_create_color_properties(&plane->base,
 					  BIT(DRM_COLOR_YCBCR_BT601) |

-- 
2.51.2

[PATCH v3 10/33] drm/vkms: Introduce configfs for plane rotation

[Louis Chauvet]

To allows the userspace to test many hardware configurations, introduce a
new interface to configure the available rotation per planes. VKMS
supports any rotation and reflection, so the userspace can choose any
combination.

The supported rotations are configured by writing a rotation bitmask to
the file `supported_rotations` and the default rotation is chosen by
writing a rotation bitmask to `default_rotation`.

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 Documentation/ABI/testing/configfs-vkms | 15 ++++++
 Documentation/gpu/vkms.rst              |  7 ++-
 drivers/gpu/drm/vkms/vkms_configfs.c    | 93 ++++++++++++++++++++++++++++++---
 3 files changed, 108 insertions(+), 7 deletions(-)

diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
index 6fe375d1636f..9b74375bbf35 100644
--- a/Documentation/ABI/testing/configfs-vkms
+++ b/Documentation/ABI/testing/configfs-vkms
@@ -109,6 +109,21 @@ Contact:	dri-devel@lists.freedesktop.org
 Description:
         Name of the plane.
 
+What:		/sys/kernel/config/vkms/<device>/planes/<plane>/possible_rotations
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        Available rotations for the plane, as a bitmask:
+        0x01 - no rotation, 0x02 - rotate 90°, 0x04 - rotate 180°,
+        0x08 - rotate 270°, 0x10 - reflect x, 0x20 - reflect y.
+
+What:		/sys/kernel/config/vkms/<device>/planes/<plane>/default_rotation
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        Default rotation presented to userspace, same values as
+        possible_rotations.
+
 What:		/sys/kernel/config/vkms/<device>/planes/<plane>/possible_crtcs
 Date:		Nov 2025
 Contact:	dri-devel@lists.freedesktop.org
diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index 79f1185d8645..7fd746dd6ee2 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -87,11 +87,16 @@ Start by creating one or more planes::
 
   sudo mkdir /config/vkms/my-vkms/planes/plane0
 
-Planes have 2 configurable attributes:
+Planes have 4 configurable attributes:
 
 - type: Plane type: 0 overlay, 1 primary, 2 cursor (same values as those
   exposed by the "type" property of a plane)
 - name: Name of the plane. Allowed characters are [A-Za-z1-9_-]
+- possible_rotations: Available rotation for a plane, as a bitmask: 0x01 no rotation,
+  0x02 rotate 90°, 0x04 rotate 180°, 0x08 rotate 270°, 0x10 reflect x, 0x20 reflect y
+  (same values as those exposed by the "rotation" property of a plane)
+- default_rotation: Default rotation presented to the userspace, same values as
+  possible_rotations.
 
 Continue by creating one or more CRTCs::
 
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index 989788042191..bcc3e222e6b3 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -365,24 +365,105 @@ static ssize_t plane_name_store(struct config_item *item, const char *page,
 	return (ssize_t)count;
 }
 
+static ssize_t plane_supported_rotations_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_plane *plane;
+	unsigned int plane_supported_rotations;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		plane_supported_rotations = vkms_config_plane_get_supported_rotations(plane->config);
+	}
+
+	return sprintf(page, "%u", plane_supported_rotations);
+}
+
+static ssize_t plane_supported_rotations_store(struct config_item *item,
+					       const char *page, size_t count)
+{
+	struct vkms_configfs_plane *plane = plane_item_to_vkms_configfs_plane(item);
+	int ret, val = 0;
+
+	ret = kstrtouint(page, 0, &val);
+	if (ret)
+		return ret;
+
+	/* Should be a supported value */
+	if (val & ~(DRM_MODE_ROTATE_MASK | DRM_MODE_REFLECT_MASK))
+		return -EINVAL;
+	/* Should at least provide one rotation */
+	if (!(val & DRM_MODE_ROTATE_MASK))
+		return -EINVAL;
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		if (plane->dev->enabled)
+			return -EBUSY;
+
+		vkms_config_plane_set_supported_rotations(plane->config, val);
+	}
+
+	return count;
+}
+
+static ssize_t plane_default_rotation_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_plane *plane = plane_item_to_vkms_configfs_plane(item);
+	unsigned int plane_default_rotation;
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		plane_default_rotation = vkms_config_plane_get_default_rotation(plane->config);
+	}
+
+	return sprintf(page, "%u", plane_default_rotation);
+}
+
+static ssize_t plane_default_rotation_store(struct config_item *item,
+					    const char *page, size_t count)
+{
+	struct vkms_configfs_plane *plane = plane_item_to_vkms_configfs_plane(item);
+	int ret, val = 0;
+
+	ret = kstrtouint(page, 10, &val);
+	if (ret)
+		return ret;
+
+	/* Should be a supported value */
+	if (val & ~(DRM_MODE_ROTATE_MASK | DRM_MODE_REFLECT_MASK))
+		return -EINVAL;
+
+	/* Should contain exactly one rotation */
+	if (!is_power_of_2(val & DRM_MODE_ROTATE_MASK))
+		return -EINVAL;
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		if (plane->dev->enabled)
+			return -EBUSY;
+
+		vkms_config_plane_set_default_rotation(plane->config, val);
+	}
+
+	return count;
+}
+
 CONFIGFS_ATTR(plane_, type);
 CONFIGFS_ATTR(plane_, name);
+CONFIGFS_ATTR(plane_, supported_rotations);
+CONFIGFS_ATTR(plane_, default_rotation);
 
 static struct configfs_attribute *plane_item_attrs[] = {
 	&plane_attr_type,
 	&plane_attr_name,
+	&plane_attr_supported_rotations,
+	&plane_attr_default_rotation,
 	NULL,
 };
 
 static void plane_release(struct config_item *item)
 {
-	struct vkms_configfs_plane *plane;
-	struct mutex *lock;
-
-	plane = plane_item_to_vkms_configfs_plane(item);
-	lock = &plane->dev->lock;
+	struct vkms_configfs_plane *plane = plane_item_to_vkms_configfs_plane(item);
 
-	scoped_guard(mutex, lock) {
+	scoped_guard(mutex, &plane->dev->lock) {
 		vkms_config_destroy_plane(plane->config);
 		kfree(plane);
 	}

-- 
2.51.2

[PATCH v3 11/33] drm/drm_color_mgmt: Expose drm_get_color_encoding_name

[Louis Chauvet]

drm_get_color_encoding_name can be useful to display debug information
outside drm core. Export it so it could be used for VKMS

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/drm_color_mgmt.c    | 2 +-
 drivers/gpu/drm/drm_crtc_internal.h | 2 --
 include/drm/drm_color_mgmt.h        | 2 ++
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/drm_color_mgmt.c b/drivers/gpu/drm/drm_color_mgmt.c
index c598b99673fc..56fd8e0620dd 100644
--- a/drivers/gpu/drm/drm_color_mgmt.c
+++ b/drivers/gpu/drm/drm_color_mgmt.c
@@ -496,7 +496,7 @@ const char *drm_get_color_encoding_name(enum drm_color_encoding encoding)
 
 	return color_encoding_name[encoding];
 }
-EXPORT_SYMBOL_IF_KUNIT(drm_get_color_encoding_name);
+EXPORT_SYMBOL(drm_get_color_encoding_name);
 
 /**
  * drm_get_color_range_name - return a string for color range
diff --git a/drivers/gpu/drm/drm_crtc_internal.h b/drivers/gpu/drm/drm_crtc_internal.h
index c09409229644..2f22b1a16dfa 100644
--- a/drivers/gpu/drm/drm_crtc_internal.h
+++ b/drivers/gpu/drm/drm_crtc_internal.h
@@ -38,7 +38,6 @@
 #include <linux/err.h>
 #include <linux/types.h>
 
-enum drm_color_encoding;
 enum drm_color_range;
 enum drm_connector_force;
 enum drm_mode_status;
@@ -121,7 +120,6 @@ int drm_mode_destroy_dumb_ioctl(struct drm_device *dev,
 				void *data, struct drm_file *file_priv);
 
 /* drm_color_mgmt.c */
-const char *drm_get_color_encoding_name(enum drm_color_encoding encoding);
 const char *drm_get_color_range_name(enum drm_color_range range);
 
 /* IOCTLs */
diff --git a/include/drm/drm_color_mgmt.h b/include/drm/drm_color_mgmt.h
index 5140691f476a..133ca77d91c7 100644
--- a/include/drm/drm_color_mgmt.h
+++ b/include/drm/drm_color_mgmt.h
@@ -113,6 +113,8 @@ enum drm_color_range {
 	DRM_COLOR_RANGE_MAX,
 };
 
+const char *drm_get_color_encoding_name(enum drm_color_encoding encoding);
+
 int drm_plane_create_color_properties(struct drm_plane *plane,
 				      u32 supported_encodings,
 				      u32 supported_ranges,

-- 
2.51.2

[PATCH v3 12/33] drm/vkms: Introduce config for plane color encoding

[Louis Chauvet]

VKMS driver supports all the color encoding on planes, but for testing it
can be useful to only advertise few of them. This new configuration
interface will allow configuring the color encoding per planes.

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/tests/vkms_config_test.c | 51 +++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_config.c            | 32 ++++++++++++++
 drivers/gpu/drm/vkms/vkms_config.h            | 64 +++++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_plane.c             | 15 +++----
 4 files changed, 154 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/vkms/tests/vkms_config_test.c b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
index c33fe737678f..a2a3f1a106a3 100644
--- a/drivers/gpu/drm/vkms/tests/vkms_config_test.c
+++ b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
@@ -192,6 +192,14 @@ static void vkms_config_test_default_config(struct kunit *test)
 		KUNIT_EXPECT_EQ(test,
 				vkms_config_plane_get_default_rotation(plane_cfg),
 				DRM_MODE_ROTATE_0);
+		KUNIT_EXPECT_EQ(test,
+				vkms_config_plane_get_supported_color_encodings(plane_cfg),
+				BIT(DRM_COLOR_YCBCR_BT601) |
+				BIT(DRM_COLOR_YCBCR_BT709) |
+				BIT(DRM_COLOR_YCBCR_BT2020));
+		KUNIT_EXPECT_EQ(test,
+				vkms_config_plane_get_default_color_encoding(plane_cfg),
+				DRM_COLOR_YCBCR_BT601);
 	}
 
 	/* Encoders */
@@ -526,6 +534,48 @@ static void vkms_config_test_valid_plane_rotations(struct kunit *test)
 	vkms_config_destroy(config);
 }
 
+static void vkms_config_test_valid_plane_color_encoding(struct kunit *test)
+{
+	struct vkms_config *config;
+	struct vkms_config_plane *plane_cfg;
+
+	config = vkms_config_default_create(false, false, false, false);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, config);
+
+	plane_cfg = get_first_plane(config);
+
+	/* Valid, all color encoding supported */
+	vkms_config_plane_set_supported_color_encodings(plane_cfg,
+							BIT(DRM_COLOR_YCBCR_BT601) |
+							BIT(DRM_COLOR_YCBCR_BT709) |
+							BIT(DRM_COLOR_YCBCR_BT2020));
+	vkms_config_plane_set_default_color_encoding(plane_cfg, DRM_COLOR_YCBCR_BT601);
+	KUNIT_EXPECT_TRUE(test, vkms_config_valid_plane_color_encoding(config, plane_cfg));
+	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
+
+	/* Invalid, default color encoding is not supported */
+	vkms_config_plane_set_supported_color_encodings(plane_cfg,
+							BIT(DRM_COLOR_YCBCR_BT601) |
+							BIT(DRM_COLOR_YCBCR_BT2020));
+	vkms_config_plane_set_default_color_encoding(plane_cfg, DRM_COLOR_YCBCR_BT709);
+	KUNIT_EXPECT_FALSE(test, vkms_config_valid_plane_color_encoding(config, plane_cfg));
+	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
+
+	/* Valid, no supported or color encoding */
+	vkms_config_plane_set_supported_color_encodings(plane_cfg, 0);
+	vkms_config_plane_set_default_color_encoding(plane_cfg, 0);
+	KUNIT_EXPECT_TRUE(test, vkms_config_valid_plane_color_encoding(config, plane_cfg));
+	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
+
+	/* Valid, if no supported color encoding, default is ignored */
+	vkms_config_plane_set_supported_color_encodings(plane_cfg, 0);
+	vkms_config_plane_set_default_color_encoding(plane_cfg, DRM_COLOR_YCBCR_BT601);
+	KUNIT_EXPECT_TRUE(test, vkms_config_valid_plane_color_encoding(config, plane_cfg));
+	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
+
+	vkms_config_destroy(config);
+}
+
 static void vkms_config_test_valid_plane_possible_crtcs(struct kunit *test)
 {
 	struct vkms_config *config;
@@ -1049,6 +1099,7 @@ static struct kunit_case vkms_config_test_cases[] = {
 	KUNIT_CASE(vkms_config_test_invalid_plane_number),
 	KUNIT_CASE(vkms_config_test_valid_plane_type),
 	KUNIT_CASE(vkms_config_test_valid_plane_rotations),
+	KUNIT_CASE(vkms_config_test_valid_plane_color_encoding),
 	KUNIT_CASE(vkms_config_test_valid_plane_possible_crtcs),
 	KUNIT_CASE(vkms_config_test_invalid_crtc_number),
 	KUNIT_CASE(vkms_config_test_invalid_encoder_number),
diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
index 7aa087602807..486cdd1f54a4 100644
--- a/drivers/gpu/drm/vkms/vkms_config.c
+++ b/drivers/gpu/drm/vkms/vkms_config.c
@@ -179,6 +179,25 @@ bool vkms_config_valid_plane_rotation(const struct vkms_config *config,
 }
 EXPORT_SYMBOL_IF_KUNIT(vkms_config_valid_plane_rotation);
 
+VISIBLE_IF_KUNIT
+bool vkms_config_valid_plane_color_encoding(const struct vkms_config *config,
+					    const struct vkms_config_plane *plane_cfg)
+{
+	struct drm_device *dev = config->dev ? &config->dev->drm : NULL;
+
+	if (vkms_config_plane_get_supported_color_encodings(plane_cfg)) {
+		if ((BIT(vkms_config_plane_get_default_color_encoding(plane_cfg)) &
+		     vkms_config_plane_get_supported_color_encodings(plane_cfg)) !=
+		    BIT(vkms_config_plane_get_default_color_encoding(plane_cfg))) {
+			drm_info(dev, "Configured default color encoding is not supported by the plane\n");
+			return false;
+		}
+	}
+
+	return true;
+}
+EXPORT_SYMBOL_IF_KUNIT(vkms_config_valid_plane_color_encoding);
+
 static bool valid_planes_for_crtc(const struct vkms_config *config,
 				  struct vkms_config_crtc *crtc_cfg)
 {
@@ -341,6 +360,9 @@ bool vkms_config_is_valid(const struct vkms_config *config)
 	vkms_config_for_each_plane(config, plane_cfg) {
 		if (!vkms_config_valid_plane_rotation(config, plane_cfg))
 			return false;
+
+		if (!vkms_config_valid_plane_color_encoding(config, plane_cfg))
+			return false;
 	}
 
 	if (!valid_plane_number(config))
@@ -418,6 +440,12 @@ static int vkms_config_show(struct seq_file *m, void *data)
 		show_bitfield(m, vkms_config_plane_get_default_rotation(plane_cfg),
 			      drm_get_rotation_name);
 		seq_puts(m, "\n");
+		seq_puts(m, "\tsupported color encoding=");
+		show_bitfield(m, vkms_config_plane_get_supported_color_encodings(plane_cfg),
+			      drm_get_color_encoding_name);
+		seq_puts(m, "\n");
+		seq_printf(m, "\tdefault color encoding=%s\n",
+			   drm_get_color_encoding_name(vkms_config_plane_get_default_color_encoding(plane_cfg)));
 	}
 
 	vkms_config_for_each_crtc(vkmsdev->config, crtc_cfg) {
@@ -463,6 +491,10 @@ struct vkms_config_plane *vkms_config_create_plane(struct vkms_config *config)
 	vkms_config_plane_set_supported_rotations(plane_cfg,
 						  DRM_MODE_ROTATE_MASK | DRM_MODE_REFLECT_MASK);
 	vkms_config_plane_set_default_rotation(plane_cfg, DRM_MODE_ROTATE_0);
+	vkms_config_plane_set_supported_color_encodings(plane_cfg, BIT(DRM_COLOR_YCBCR_BT601) |
+							BIT(DRM_COLOR_YCBCR_BT709) |
+							BIT(DRM_COLOR_YCBCR_BT2020));
+	vkms_config_plane_set_default_color_encoding(plane_cfg, DRM_COLOR_YCBCR_BT601);
 
 	xa_init_flags(&plane_cfg->possible_crtcs, XA_FLAGS_ALLOC);
 
diff --git a/drivers/gpu/drm/vkms/vkms_config.h b/drivers/gpu/drm/vkms/vkms_config.h
index cf29976ec1a9..cae7c3b3da07 100644
--- a/drivers/gpu/drm/vkms/vkms_config.h
+++ b/drivers/gpu/drm/vkms/vkms_config.h
@@ -45,6 +45,8 @@ struct vkms_config {
  *         It can be used to store a temporary reference to a VKMS plane during
  *         device creation. This pointer is not managed by the configuration and
  *         must be managed by other means.
+ * @default_color_encoding: Default color encoding that should be used by this plane
+ * @supported_color_encodings: Color encodings that this plane will support
  */
 struct vkms_config_plane {
 	struct list_head link;
@@ -54,6 +56,8 @@ struct vkms_config_plane {
 	enum drm_plane_type type;
 	unsigned int default_rotation;
 	unsigned int supported_rotations;
+	enum drm_color_encoding default_color_encoding;
+	unsigned int supported_color_encodings;
 	struct xarray possible_crtcs;
 	bool default_pipeline;
 
@@ -375,6 +379,66 @@ bool vkms_config_valid_plane_rotation(const struct vkms_config *config,
 				      const struct vkms_config_plane *plane_cfg);
 #endif
 
+/**
+ * vkms_config_plane_get_default_color_encoding() - Get the default color encoding for a plane
+ * @plane_cfg: Plane to get the default color encoding from
+ *
+ * Returns:
+ * The default color encoding for the plane
+ */
+static inline enum drm_color_encoding
+vkms_config_plane_get_default_color_encoding(const struct vkms_config_plane *plane_cfg)
+{
+	return plane_cfg->default_color_encoding;
+}
+
+/**
+ * vkms_config_plane_set_default_color_encoding() - Set the default color encoding for a plane
+ * @plane_cfg: Plane to set the default color encoding to
+ * @default_color_encoding: New default color encoding for the plane
+ */
+static inline void
+vkms_config_plane_set_default_color_encoding(struct vkms_config_plane *plane_cfg,
+					     enum drm_color_encoding default_color_encoding)
+{
+	plane_cfg->default_color_encoding = default_color_encoding;
+}
+
+/**
+ * vkms_config_plane_get_supported_color_encodings() - Get the supported color encodings for a plane
+ * @plane_cfg: Plane to get the supported color encodings from
+ *
+ * Returns:
+ * The supported color encodings for the plane. Each set bit correspond to a value of enum
+ * drm_color_encoding: BIT(DRM_COLOR_YCBCR_BT601) | BIT(DRM_COLOR_YCBCR_BT709) means that
+ * DRM_COLOR_YCBCR_BT601 and DRM_COLOR_YCBCR_BT709 are supported.
+ */
+static inline unsigned int
+vkms_config_plane_get_supported_color_encodings(const struct vkms_config_plane *plane_cfg)
+{
+	return plane_cfg->supported_color_encodings;
+}
+
+/**
+ * vkms_config_plane_set_supported_color_encodings() - Set the supported color encodings for a plane
+ * @plane_cfg: Plane to set the supported color encodings to
+ * @supported_color_encodings: New supported color encodings for the plane. Each set bit corresponds
+ *                            to a value of enum drm_color_encoding:
+ *                            BIT(DRM_COLOR_YCBCR_BT601) | BIT(DRM_COLOR_YCBCR_BT709) means that
+ *                            DRM_COLOR_YCBCR_BT601 and DRM_COLOR_YCBCR_BT709 are supported.
+ */
+static inline void
+vkms_config_plane_set_supported_color_encodings(struct vkms_config_plane *plane_cfg,
+						unsigned int supported_color_encodings)
+{
+	plane_cfg->supported_color_encodings = supported_color_encodings;
+}
+
+#if IS_ENABLED(CONFIG_KUNIT)
+bool vkms_config_valid_plane_color_encoding(const struct vkms_config *config,
+					    const struct vkms_config_plane *plane_cfg);
+#endif
+
 /**
  * vkms_config_plane_set_name() - Set the plane name
  * @plane_cfg: Plane to set the name to
diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
index 7c604cfd6a09..49544839f7dd 100644
--- a/drivers/gpu/drm/vkms/vkms_plane.c
+++ b/drivers/gpu/drm/vkms/vkms_plane.c
@@ -239,14 +239,13 @@ struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev,
 					   vkms_config_plane_get_default_rotation(plane_cfg),
 					   vkms_config_plane_get_supported_rotations(plane_cfg));
 
-	drm_plane_create_color_properties(&plane->base,
-					  BIT(DRM_COLOR_YCBCR_BT601) |
-					  BIT(DRM_COLOR_YCBCR_BT709) |
-					  BIT(DRM_COLOR_YCBCR_BT2020),
-					  BIT(DRM_COLOR_YCBCR_LIMITED_RANGE) |
-					  BIT(DRM_COLOR_YCBCR_FULL_RANGE),
-					  DRM_COLOR_YCBCR_BT601,
-					  DRM_COLOR_YCBCR_FULL_RANGE);
+	if (vkms_config_plane_get_supported_color_encodings(plane_cfg) != 0)
+		drm_plane_create_color_properties(&plane->base,
+						  vkms_config_plane_get_supported_color_encodings(plane_cfg),
+						  BIT(DRM_COLOR_YCBCR_LIMITED_RANGE) |
+						  BIT(DRM_COLOR_YCBCR_FULL_RANGE),
+						  vkms_config_plane_get_default_color_encoding(plane_cfg),
+						  DRM_COLOR_YCBCR_FULL_RANGE);
 
 	if (vkms_config_plane_get_default_pipeline(plane_cfg))
 		vkms_initialize_colorops(&plane->base);

-- 
2.51.2

[PATCH v3 13/33] drm/vkms: Introduce configfs for plane color encoding

[Louis Chauvet]

To allows the userspace to test many hardware configuration, introduce a
new interface to configure the available color encoding per planes. VKMS
supports multiple color encoding, so the userspace can choose any
combination.

The supported color encoding are configured by writing a color encoding
bitmask to the file `supported_color_encoding` and the default color
encoding is chosen by writing a color encoding bitmask to
`default_color_encoding`.

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 Documentation/ABI/testing/configfs-vkms | 14 +++++
 Documentation/gpu/vkms.rst              |  8 ++-
 drivers/gpu/drm/vkms/vkms_configfs.c    | 97 +++++++++++++++++++++++++++++++++
 3 files changed, 118 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
index 9b74375bbf35..242aae91289c 100644
--- a/Documentation/ABI/testing/configfs-vkms
+++ b/Documentation/ABI/testing/configfs-vkms
@@ -124,6 +124,20 @@ Description:
         Default rotation presented to userspace, same values as
         possible_rotations.
 
+What:		/sys/kernel/config/vkms/<device>/planes/<plane>/supported_color_encoding
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        Available color encodings for the plane, as a bitmask:
+        0x01 - YCBCR_BT601, 0x02 - YCBCR_BT709, 0x04 - YCBCR_BT2020.
+
+What:		/sys/kernel/config/vkms/<device>/planes/<plane>/default_color_encoding
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        Default color encoding presented to userspace, same
+        values as supported_color_encoding.
+
 What:		/sys/kernel/config/vkms/<device>/planes/<plane>/possible_crtcs
 Date:		Nov 2025
 Contact:	dri-devel@lists.freedesktop.org
diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index 7fd746dd6ee2..0d4dae3ba8e5 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -87,7 +87,7 @@ Start by creating one or more planes::
 
   sudo mkdir /config/vkms/my-vkms/planes/plane0
 
-Planes have 4 configurable attributes:
+Planes have 6 configurable attributes:
 
 - type: Plane type: 0 overlay, 1 primary, 2 cursor (same values as those
   exposed by the "type" property of a plane)
@@ -97,6 +97,12 @@ Planes have 4 configurable attributes:
   (same values as those exposed by the "rotation" property of a plane)
 - default_rotation: Default rotation presented to the userspace, same values as
   possible_rotations.
+- supported_color_encodings: Available encodings for a plane, as a bitmask:
+  0x01 YCBCR_BT601, 0x02 YCBCR_BT709, 0x04 YCBCR_BT2020 (same values as those exposed
+  by the COLOR_ENCODING property of a plane). If set, supported_color_range
+  must be set too.
+- default_color_encoding: Default color encoding presented to the userspace, same
+  values as supported_color_encodings
 
 Continue by creating one or more CRTCs::
 
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index bcc3e222e6b3..755978b17c95 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -9,6 +9,14 @@
 #include "vkms_configfs.h"
 #include "vkms_connector.h"
 
+/**
+ * VKMS_SUPPORTED_COLOR_ENCODINGS - Bitmask of all supported color encodings in VKMS
+ */
+#define VKMS_SUPPORTED_COLOR_ENCODINGS (	\
+	BIT(DRM_COLOR_YCBCR_BT601) |		\
+	BIT(DRM_COLOR_YCBCR_BT709) |		\
+	BIT(DRM_COLOR_YCBCR_BT2020))
+
 /* To avoid registering configfs more than once or unregistering on error */
 static bool is_configfs_registered;
 
@@ -446,16 +454,105 @@ static ssize_t plane_default_rotation_store(struct config_item *item,
 	return count;
 }
 
+static ssize_t plane_supported_color_encodings_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_plane *plane = plane_item_to_vkms_configfs_plane(item);
+	unsigned int supported_color_encodings;
+
+	scoped_guard(mutex, &plane->dev->lock)
+		supported_color_encodings = vkms_config_plane_get_supported_color_encodings(plane->config);
+
+	return sprintf(page, "%u", supported_color_encodings);
+}
+
+static ssize_t plane_supported_color_encodings_store(struct config_item *item,
+						     const char *page, size_t count)
+{
+	struct vkms_configfs_plane *plane = plane_item_to_vkms_configfs_plane(item);
+	int ret, val = 0;
+
+	ret = kstrtouint(page, 10, &val);
+	if (ret)
+		return ret;
+
+	/* Should be a supported value */
+	if (val & ~(VKMS_SUPPORTED_COLOR_ENCODINGS))
+		return -EINVAL;
+	/* Should at least provide one color range */
+	if ((val & (VKMS_SUPPORTED_COLOR_ENCODINGS)) == 0)
+		return -EINVAL;
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		if (plane->dev->enabled)
+			return -EBUSY;
+
+		vkms_config_plane_set_supported_color_encodings(plane->config, val);
+	}
+
+	return count;
+}
+
+static ssize_t plane_default_color_encoding_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_plane *plane;
+	unsigned int default_color_encoding;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+
+	scoped_guard(mutex, &plane->dev->lock)
+		default_color_encoding = BIT(vkms_config_plane_get_default_color_encoding(plane->config));
+
+	return sprintf(page, "%u", default_color_encoding);
+}
+
+static ssize_t plane_default_color_encoding_store(struct config_item *item,
+						  const char *page, size_t count)
+{
+	struct vkms_configfs_plane *plane = plane_item_to_vkms_configfs_plane(item);
+	int ret, val = 0;
+
+	ret = kstrtouint(page, 10, &val);
+	if (ret)
+		return ret;
+
+	/* Should be a supported value */
+	if (val & ~VKMS_SUPPORTED_COLOR_ENCODINGS)
+		return -EINVAL;
+	/* Should at least provide one color range */
+	if ((val & VKMS_SUPPORTED_COLOR_ENCODINGS) == 0)
+		return -EINVAL;
+
+	/* Ensure val is a single bit set */
+	if (!is_power_of_2(val))
+		return -EINVAL;
+
+	/* Convert bit position to the proper enum value */
+	val = __ffs(val) + DRM_COLOR_YCBCR_BT601;
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		if (plane->dev->enabled)
+			return -EBUSY;
+
+		vkms_config_plane_set_default_color_encoding(plane->config, val);
+	}
+
+	return count;
+}
+
 CONFIGFS_ATTR(plane_, type);
 CONFIGFS_ATTR(plane_, name);
 CONFIGFS_ATTR(plane_, supported_rotations);
 CONFIGFS_ATTR(plane_, default_rotation);
+CONFIGFS_ATTR(plane_, supported_color_encodings);
+CONFIGFS_ATTR(plane_, default_color_encoding);
 
 static struct configfs_attribute *plane_item_attrs[] = {
 	&plane_attr_type,
 	&plane_attr_name,
 	&plane_attr_supported_rotations,
 	&plane_attr_default_rotation,
+	&plane_attr_supported_color_encodings,
+	&plane_attr_default_color_encoding,
 	NULL,
 };
 

-- 
2.51.2

[PATCH v3 14/33] drm/drm_color_mgmt: Expose drm_get_color_range_name

[Louis Chauvet]

drm_get_color_range_name can be useful to print debugging information.
Export it so it could be used from VKMS.

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/drm_color_mgmt.c    | 2 +-
 drivers/gpu/drm/drm_crtc_internal.h | 4 ----
 include/drm/drm_color_mgmt.h        | 1 +
 3 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/drm_color_mgmt.c b/drivers/gpu/drm/drm_color_mgmt.c
index 56fd8e0620dd..beced449ecf1 100644
--- a/drivers/gpu/drm/drm_color_mgmt.c
+++ b/drivers/gpu/drm/drm_color_mgmt.c
@@ -512,7 +512,7 @@ const char *drm_get_color_range_name(enum drm_color_range range)
 
 	return color_range_name[range];
 }
-EXPORT_SYMBOL_IF_KUNIT(drm_get_color_range_name);
+EXPORT_SYMBOL(drm_get_color_range_name);
 
 /**
  * drm_plane_create_color_properties - color encoding related plane properties
diff --git a/drivers/gpu/drm/drm_crtc_internal.h b/drivers/gpu/drm/drm_crtc_internal.h
index 2f22b1a16dfa..54bd491fbfba 100644
--- a/drivers/gpu/drm/drm_crtc_internal.h
+++ b/drivers/gpu/drm/drm_crtc_internal.h
@@ -38,7 +38,6 @@
 #include <linux/err.h>
 #include <linux/types.h>
 
-enum drm_color_range;
 enum drm_connector_force;
 enum drm_mode_status;
 
@@ -119,9 +118,6 @@ int drm_mode_mmap_dumb_ioctl(struct drm_device *dev,
 int drm_mode_destroy_dumb_ioctl(struct drm_device *dev,
 				void *data, struct drm_file *file_priv);
 
-/* drm_color_mgmt.c */
-const char *drm_get_color_range_name(enum drm_color_range range);
-
 /* IOCTLs */
 int drm_mode_gamma_get_ioctl(struct drm_device *dev,
 			     void *data, struct drm_file *file_priv);
diff --git a/include/drm/drm_color_mgmt.h b/include/drm/drm_color_mgmt.h
index 133ca77d91c7..e91f494e5a63 100644
--- a/include/drm/drm_color_mgmt.h
+++ b/include/drm/drm_color_mgmt.h
@@ -114,6 +114,7 @@ enum drm_color_range {
 };
 
 const char *drm_get_color_encoding_name(enum drm_color_encoding encoding);
+const char *drm_get_color_range_name(enum drm_color_range range);
 
 int drm_plane_create_color_properties(struct drm_plane *plane,
 				      u32 supported_encodings,

-- 
2.51.2

[PATCH v3 15/33] drm/vkms: Introduce config for plane color range

[Louis Chauvet]

VKMS driver supports all the color range on planes, but for testing it can
be useful to only advertise few of them. This new configuration interface
will allow configuring the color range per planes.

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/tests/vkms_config_test.c | 44 +++++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_config.c            | 39 ++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_config.h            | 35 +++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_plane.c             |  8 ++---
 4 files changed, 122 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/vkms/tests/vkms_config_test.c b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
index a2a3f1a106a3..a88d8b4a969e 100644
--- a/drivers/gpu/drm/vkms/tests/vkms_config_test.c
+++ b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0+
 
+#include <drm/drm_color_mgmt.h>
 #include <drm/drm_mode.h>
 #include <kunit/test.h>
 
@@ -562,6 +563,7 @@ static void vkms_config_test_valid_plane_color_encoding(struct kunit *test)
 	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
 
 	/* Valid, no supported or color encoding */
+	vkms_config_plane_set_supported_color_ranges(plane_cfg, 0);
 	vkms_config_plane_set_supported_color_encodings(plane_cfg, 0);
 	vkms_config_plane_set_default_color_encoding(plane_cfg, 0);
 	KUNIT_EXPECT_TRUE(test, vkms_config_valid_plane_color_encoding(config, plane_cfg));
@@ -576,6 +578,47 @@ static void vkms_config_test_valid_plane_color_encoding(struct kunit *test)
 	vkms_config_destroy(config);
 }
 
+static void vkms_config_test_valid_plane_color_range(struct kunit *test)
+{
+	struct vkms_config *config;
+	struct vkms_config_plane *plane_cfg;
+
+	config = vkms_config_default_create(false, false, false, false);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, config);
+
+	plane_cfg = get_first_plane(config);
+
+	/* Valid, all color range supported */
+	vkms_config_plane_set_supported_color_ranges(plane_cfg,
+						     BIT(DRM_COLOR_YCBCR_LIMITED_RANGE) |
+						     BIT(DRM_COLOR_YCBCR_FULL_RANGE));
+	vkms_config_plane_set_default_color_range(plane_cfg, DRM_COLOR_YCBCR_FULL_RANGE);
+	KUNIT_EXPECT_TRUE(test, vkms_config_valid_plane_color_range(config, plane_cfg));
+	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
+
+	/* Invalid, default color range is not supported */
+	vkms_config_plane_set_supported_color_ranges(plane_cfg,
+						     BIT(DRM_COLOR_YCBCR_FULL_RANGE));
+	vkms_config_plane_set_default_color_range(plane_cfg, DRM_COLOR_YCBCR_LIMITED_RANGE);
+	KUNIT_EXPECT_FALSE(test, vkms_config_valid_plane_color_range(config, plane_cfg));
+	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
+
+	/* Valid, no supported or color range */
+	vkms_config_plane_set_supported_color_encodings(plane_cfg, 0);
+	vkms_config_plane_set_supported_color_ranges(plane_cfg, 0);
+	vkms_config_plane_set_default_color_range(plane_cfg, 0);
+	KUNIT_EXPECT_TRUE(test, vkms_config_valid_plane_color_range(config, plane_cfg));
+	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
+
+	/* Valid, if no supported color range, default is ignored */
+	vkms_config_plane_set_supported_color_ranges(plane_cfg, 0);
+	vkms_config_plane_set_default_color_range(plane_cfg, DRM_COLOR_YCBCR_LIMITED_RANGE);
+	KUNIT_EXPECT_TRUE(test, vkms_config_valid_plane_color_range(config, plane_cfg));
+	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
+
+	vkms_config_destroy(config);
+}
+
 static void vkms_config_test_valid_plane_possible_crtcs(struct kunit *test)
 {
 	struct vkms_config *config;
@@ -1100,6 +1143,7 @@ static struct kunit_case vkms_config_test_cases[] = {
 	KUNIT_CASE(vkms_config_test_valid_plane_type),
 	KUNIT_CASE(vkms_config_test_valid_plane_rotations),
 	KUNIT_CASE(vkms_config_test_valid_plane_color_encoding),
+	KUNIT_CASE(vkms_config_test_valid_plane_color_range),
 	KUNIT_CASE(vkms_config_test_valid_plane_possible_crtcs),
 	KUNIT_CASE(vkms_config_test_invalid_crtc_number),
 	KUNIT_CASE(vkms_config_test_invalid_encoder_number),
diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
index 486cdd1f54a4..5591e0baf1a1 100644
--- a/drivers/gpu/drm/vkms/vkms_config.c
+++ b/drivers/gpu/drm/vkms/vkms_config.c
@@ -198,6 +198,25 @@ bool vkms_config_valid_plane_color_encoding(const struct vkms_config *config,
 }
 EXPORT_SYMBOL_IF_KUNIT(vkms_config_valid_plane_color_encoding);
 
+VISIBLE_IF_KUNIT
+bool vkms_config_valid_plane_color_range(const struct vkms_config *config,
+					 const struct vkms_config_plane *plane_cfg)
+{
+	struct drm_device *dev = config->dev ? &config->dev->drm : NULL;
+
+	if (vkms_config_plane_get_supported_color_ranges(plane_cfg)) {
+		if ((BIT(vkms_config_plane_get_default_color_range(plane_cfg)) &
+		     vkms_config_plane_get_supported_color_ranges(plane_cfg)) !=
+		    BIT(vkms_config_plane_get_default_color_range(plane_cfg))) {
+			drm_info(dev, "Configured default color range is not supported by the plane\n");
+			return false;
+		}
+	}
+
+	return true;
+}
+EXPORT_SYMBOL_IF_KUNIT(vkms_config_valid_plane_color_range);
+
 static bool valid_planes_for_crtc(const struct vkms_config *config,
 				  struct vkms_config_crtc *crtc_cfg)
 {
@@ -354,6 +373,7 @@ static bool valid_connector_possible_encoders(const struct vkms_config *config)
 
 bool vkms_config_is_valid(const struct vkms_config *config)
 {
+	struct drm_device *dev = config->dev ? &config->dev->drm : NULL;
 	struct vkms_config_crtc *crtc_cfg;
 	struct vkms_config_plane *plane_cfg;
 
@@ -363,6 +383,16 @@ bool vkms_config_is_valid(const struct vkms_config *config)
 
 		if (!vkms_config_valid_plane_color_encoding(config, plane_cfg))
 			return false;
+
+		if (!vkms_config_valid_plane_color_range(config, plane_cfg))
+			return false;
+
+		if ((vkms_config_plane_get_supported_color_encodings(plane_cfg) == 0) !=
+		    (vkms_config_plane_get_supported_color_ranges(plane_cfg) == 0)) {
+			drm_info(dev,
+				 "Both supported color encodings and color ranges must be set, or none\n");
+			return false;
+		}
 	}
 
 	if (!valid_plane_number(config))
@@ -446,6 +476,12 @@ static int vkms_config_show(struct seq_file *m, void *data)
 		seq_puts(m, "\n");
 		seq_printf(m, "\tdefault color encoding=%s\n",
 			   drm_get_color_encoding_name(vkms_config_plane_get_default_color_encoding(plane_cfg)));
+		seq_puts(m, "\tsupported color ranges=");
+		show_bitfield(m, vkms_config_plane_get_supported_color_ranges(plane_cfg),
+			      drm_get_color_range_name);
+		seq_puts(m, "\n");
+		seq_printf(m, "\tdefault color range=%s\n",
+			   drm_get_color_range_name(vkms_config_plane_get_default_color_range(plane_cfg)));
 	}
 
 	vkms_config_for_each_crtc(vkmsdev->config, crtc_cfg) {
@@ -495,6 +531,9 @@ struct vkms_config_plane *vkms_config_create_plane(struct vkms_config *config)
 							BIT(DRM_COLOR_YCBCR_BT709) |
 							BIT(DRM_COLOR_YCBCR_BT2020));
 	vkms_config_plane_set_default_color_encoding(plane_cfg, DRM_COLOR_YCBCR_BT601);
+	vkms_config_plane_set_supported_color_ranges(plane_cfg, BIT(DRM_COLOR_YCBCR_LIMITED_RANGE) |
+								BIT(DRM_COLOR_YCBCR_FULL_RANGE));
+	vkms_config_plane_set_default_color_range(plane_cfg, DRM_COLOR_YCBCR_FULL_RANGE);
 
 	xa_init_flags(&plane_cfg->possible_crtcs, XA_FLAGS_ALLOC);
 
diff --git a/drivers/gpu/drm/vkms/vkms_config.h b/drivers/gpu/drm/vkms/vkms_config.h
index cae7c3b3da07..bb2721a18d61 100644
--- a/drivers/gpu/drm/vkms/vkms_config.h
+++ b/drivers/gpu/drm/vkms/vkms_config.h
@@ -47,6 +47,8 @@ struct vkms_config {
  *         must be managed by other means.
  * @default_color_encoding: Default color encoding that should be used by this plane
  * @supported_color_encodings: Color encodings that this plane will support
+ * @default_color_range: Default color range that should be used by this plane
+ * @supported_color_ranges: Color ranges that this plane will support
  */
 struct vkms_config_plane {
 	struct list_head link;
@@ -58,6 +60,8 @@ struct vkms_config_plane {
 	unsigned int supported_rotations;
 	enum drm_color_encoding default_color_encoding;
 	unsigned int supported_color_encodings;
+	enum drm_color_range default_color_range;
+	unsigned int supported_color_ranges;
 	struct xarray possible_crtcs;
 	bool default_pipeline;
 
@@ -439,6 +443,37 @@ bool vkms_config_valid_plane_color_encoding(const struct vkms_config *config,
 					    const struct vkms_config_plane *plane_cfg);
 #endif
 
+static inline enum drm_color_range
+vkms_config_plane_get_default_color_range(const struct vkms_config_plane *plane_cfg)
+{
+	return plane_cfg->default_color_range;
+}
+
+static inline void
+vkms_config_plane_set_default_color_range(struct vkms_config_plane *plane_cfg,
+					  enum drm_color_range default_color_range)
+{
+	plane_cfg->default_color_range = default_color_range;
+}
+
+static inline unsigned int
+vkms_config_plane_get_supported_color_ranges(const struct vkms_config_plane *plane_cfg)
+{
+	return plane_cfg->supported_color_ranges;
+}
+
+static inline void
+vkms_config_plane_set_supported_color_ranges(struct vkms_config_plane *plane_cfg,
+					     unsigned int supported_color_ranges)
+{
+	plane_cfg->supported_color_ranges = supported_color_ranges;
+}
+
+#if IS_ENABLED(CONFIG_KUNIT)
+bool vkms_config_valid_plane_color_range(const struct vkms_config *config,
+					 const struct vkms_config_plane *plane_cfg);
+#endif
+
 /**
  * vkms_config_plane_set_name() - Set the plane name
  * @plane_cfg: Plane to set the name to
diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
index 49544839f7dd..6461cf025a27 100644
--- a/drivers/gpu/drm/vkms/vkms_plane.c
+++ b/drivers/gpu/drm/vkms/vkms_plane.c
@@ -239,13 +239,13 @@ struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev,
 					   vkms_config_plane_get_default_rotation(plane_cfg),
 					   vkms_config_plane_get_supported_rotations(plane_cfg));
 
-	if (vkms_config_plane_get_supported_color_encodings(plane_cfg) != 0)
+	if (vkms_config_plane_get_supported_color_encodings(plane_cfg) != 0 &&
+	    vkms_config_plane_get_supported_color_ranges(plane_cfg) != 0)
 		drm_plane_create_color_properties(&plane->base,
 						  vkms_config_plane_get_supported_color_encodings(plane_cfg),
-						  BIT(DRM_COLOR_YCBCR_LIMITED_RANGE) |
-						  BIT(DRM_COLOR_YCBCR_FULL_RANGE),
+						  vkms_config_plane_get_supported_color_ranges(plane_cfg),
 						  vkms_config_plane_get_default_color_encoding(plane_cfg),
-						  DRM_COLOR_YCBCR_FULL_RANGE);
+						  vkms_config_plane_get_default_color_range(plane_cfg));
 
 	if (vkms_config_plane_get_default_pipeline(plane_cfg))
 		vkms_initialize_colorops(&plane->base);

-- 
2.51.2

[PATCH v3 16/33] drm/vkms: Introduce configfs for plane color range

[Louis Chauvet]

To allows the userspace to test many hardware configuration, introduce a
new interface to configure the available color ranges per planes. VKMS
supports multiple color ranges, so the userspace can choose any
combination.

The supported color ranges are configured by writing a color range bitmask
to the file `supported_color_ranges` and the default color range is
chosen by writing a color encoding bitmask to `default_color_range`.

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 Documentation/ABI/testing/configfs-vkms | 15 ++++++
 Documentation/gpu/vkms.rst              | 10 +++-
 drivers/gpu/drm/vkms/vkms_configfs.c    | 93 +++++++++++++++++++++++++++++++++
 3 files changed, 116 insertions(+), 2 deletions(-)

diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
index 242aae91289c..2ace79ce848a 100644
--- a/Documentation/ABI/testing/configfs-vkms
+++ b/Documentation/ABI/testing/configfs-vkms
@@ -138,6 +138,21 @@ Description:
         Default color encoding presented to userspace, same
         values as supported_color_encoding.
 
+What:		/sys/kernel/config/vkms/<device>/planes/<plane>/supported_color_ranges
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        Available color ranges for the plane, as a bitmask:
+        0x1 - DRM_COLOR_YCBCR_LIMITED_RANGE,
+        0x2 - DRM_COLOR_YCBCR_FULL_RANGE.
+
+What:		/sys/kernel/config/vkms/<device>/planes/<plane>/default_color_range
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        Default color range presented to userspace, same
+        values as supported_color_ranges.
+
 What:		/sys/kernel/config/vkms/<device>/planes/<plane>/possible_crtcs
 Date:		Nov 2025
 Contact:	dri-devel@lists.freedesktop.org
diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index 0d4dae3ba8e5..ab0eb2f97fc2 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -87,7 +87,7 @@ Start by creating one or more planes::
 
   sudo mkdir /config/vkms/my-vkms/planes/plane0
 
-Planes have 6 configurable attributes:
+Planes have 8 configurable attributes:
 
 - type: Plane type: 0 overlay, 1 primary, 2 cursor (same values as those
   exposed by the "type" property of a plane)
@@ -99,10 +99,16 @@ Planes have 6 configurable attributes:
   possible_rotations.
 - supported_color_encodings: Available encodings for a plane, as a bitmask:
   0x01 YCBCR_BT601, 0x02 YCBCR_BT709, 0x04 YCBCR_BT2020 (same values as those exposed
-  by the COLOR_ENCODING property of a plane). If set, supported_color_range
+  by the COLOR_ENCODING property of a plane). If set, supported_color_ranges
   must be set too.
 - default_color_encoding: Default color encoding presented to the userspace, same
   values as supported_color_encodings
+- supported_color_ranges: Available color range for a plane, as a bitmask:
+  0x1 DRM_COLOR_YCBCR_LIMITED_RANGE, 0x2 DRM_COLOR_YCBCR_FULL_RANGE (same values as
+  those exposed by the COLOR_RANGE property of a plane). If set, supported_color_encoding
+  must be set too.
+- default_color_range: Default color range presented to the userspace, same
+  values as supported_color_ranges
 
 Continue by creating one or more CRTCs::
 
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index 755978b17c95..7be6d10b2b68 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -17,6 +17,13 @@
 	BIT(DRM_COLOR_YCBCR_BT709) |		\
 	BIT(DRM_COLOR_YCBCR_BT2020))
 
+/**
+ * VKMS_SUPPORTED_COLOR_RANGES - Bitmask of all supported color ranges in VKMS
+ */
+#define VKMS_SUPPORTED_COLOR_RANGES (		\
+	BIT(DRM_COLOR_YCBCR_LIMITED_RANGE) |	\
+	BIT(DRM_COLOR_YCBCR_FULL_RANGE))
+
 /* To avoid registering configfs more than once or unregistering on error */
 static bool is_configfs_registered;
 
@@ -454,6 +461,88 @@ static ssize_t plane_default_rotation_store(struct config_item *item,
 	return count;
 }
 
+static ssize_t plane_supported_color_ranges_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_plane *plane = plane_item_to_vkms_configfs_plane(item);
+	unsigned int supported_color_ranges;
+
+	scoped_guard(mutex, &plane->dev->lock)
+		supported_color_ranges = vkms_config_plane_get_supported_color_ranges(plane->config);
+
+	return sprintf(page, "%u", supported_color_ranges);
+}
+
+static ssize_t plane_supported_color_ranges_store(struct config_item *item,
+						  const char *page, size_t count)
+{
+	struct vkms_configfs_plane *plane = plane_item_to_vkms_configfs_plane(item);
+	int ret, val = 0;
+
+	ret = kstrtouint(page, 10, &val);
+	if (ret)
+		return ret;
+
+	/* Should be a supported value */
+	if (val & ~VKMS_SUPPORTED_COLOR_RANGES)
+		return -EINVAL;
+	/* Should at least provide one color range */
+	if ((val & VKMS_SUPPORTED_COLOR_RANGES) == 0)
+		return -EINVAL;
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		if (plane->dev->enabled)
+			return -EBUSY;
+
+		vkms_config_plane_set_supported_color_ranges(plane->config, val);
+	}
+
+	return count;
+}
+
+static ssize_t plane_default_color_range_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_plane *plane = plane_item_to_vkms_configfs_plane(item);;
+	unsigned int default_color_range;
+
+	scoped_guard(mutex, &plane->dev->lock)
+		default_color_range = vkms_config_plane_get_default_color_range(plane->config);
+
+	return sprintf(page, "%u", default_color_range);
+}
+
+static ssize_t plane_default_color_range_store(struct config_item *item,
+					       const char *page, size_t count)
+{
+	struct vkms_configfs_plane *plane = plane_item_to_vkms_configfs_plane(item);
+	int ret, val = 0;
+
+	ret = kstrtouint(page, 10, &val);
+	if (ret)
+		return ret;
+
+	/* Should be a supported value */
+	if (val & ~VKMS_SUPPORTED_COLOR_RANGES)
+		return -EINVAL;
+	/* Should at least provide one color range */
+	if ((val & VKMS_SUPPORTED_COLOR_RANGES) == 0)
+		return -EINVAL;
+
+	if (!is_power_of_2(val))
+		return -EINVAL;
+
+	/* Convert bit position to the proper enum value */
+	val = __ffs(val) + DRM_COLOR_YCBCR_LIMITED_RANGE;
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		if (plane->dev->enabled)
+			return -EBUSY;
+
+		vkms_config_plane_set_default_color_range(plane->config, val);
+	}
+
+	return count;
+}
+
 static ssize_t plane_supported_color_encodings_show(struct config_item *item, char *page)
 {
 	struct vkms_configfs_plane *plane = plane_item_to_vkms_configfs_plane(item);
@@ -543,6 +632,8 @@ CONFIGFS_ATTR(plane_, type);
 CONFIGFS_ATTR(plane_, name);
 CONFIGFS_ATTR(plane_, supported_rotations);
 CONFIGFS_ATTR(plane_, default_rotation);
+CONFIGFS_ATTR(plane_, supported_color_ranges);
+CONFIGFS_ATTR(plane_, default_color_range);
 CONFIGFS_ATTR(plane_, supported_color_encodings);
 CONFIGFS_ATTR(plane_, default_color_encoding);
 
@@ -551,6 +642,8 @@ static struct configfs_attribute *plane_item_attrs[] = {
 	&plane_attr_name,
 	&plane_attr_supported_rotations,
 	&plane_attr_default_rotation,
+	&plane_attr_supported_color_ranges,
+	&plane_attr_default_color_range,
 	&plane_attr_supported_color_encodings,
 	&plane_attr_default_color_encoding,
 	NULL,

-- 
2.51.2

[PATCH v3 17/33] drm/vkms: Introduce config for plane format

[Louis Chauvet]

VKMS driver supports all the pixel formats for planes, but for testing it
can be useful to only advertise few of them. This new configuration
interface will allow configuring the pixel format per planes.

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/vkms_config.c | 124 +++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_config.h |  51 +++++++++++++++
 drivers/gpu/drm/vkms/vkms_plane.c  |  39 +-----------
 3 files changed, 177 insertions(+), 37 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
index 5591e0baf1a1..1c97f952bf9e 100644
--- a/drivers/gpu/drm/vkms/vkms_config.c
+++ b/drivers/gpu/drm/vkms/vkms_config.c
@@ -12,6 +12,42 @@
 
 #include "vkms_config.h"
 
+static const u32 vkms_supported_plane_formats[] = {
+	DRM_FORMAT_ARGB8888,
+	DRM_FORMAT_ABGR8888,
+	DRM_FORMAT_BGRA8888,
+	DRM_FORMAT_RGBA8888,
+	DRM_FORMAT_XRGB8888,
+	DRM_FORMAT_XBGR8888,
+	DRM_FORMAT_RGB888,
+	DRM_FORMAT_BGR888,
+	DRM_FORMAT_XRGB16161616,
+	DRM_FORMAT_XBGR16161616,
+	DRM_FORMAT_ARGB16161616,
+	DRM_FORMAT_ABGR16161616,
+	DRM_FORMAT_RGB565,
+	DRM_FORMAT_BGR565,
+	DRM_FORMAT_NV12,
+	DRM_FORMAT_NV16,
+	DRM_FORMAT_NV24,
+	DRM_FORMAT_NV21,
+	DRM_FORMAT_NV61,
+	DRM_FORMAT_NV42,
+	DRM_FORMAT_YUV420,
+	DRM_FORMAT_YUV422,
+	DRM_FORMAT_YUV444,
+	DRM_FORMAT_YVU420,
+	DRM_FORMAT_YVU422,
+	DRM_FORMAT_YVU444,
+	DRM_FORMAT_P010,
+	DRM_FORMAT_P012,
+	DRM_FORMAT_P016,
+	DRM_FORMAT_R1,
+	DRM_FORMAT_R2,
+	DRM_FORMAT_R4,
+	DRM_FORMAT_R8,
+};
+
 struct vkms_config *vkms_config_create(const char *dev_name)
 {
 	struct vkms_config *config;
@@ -441,6 +477,15 @@ static void show_bitfield(struct seq_file *m, uint32_t value, const char *callba
 	}
 }
 
+static void show_formats(struct seq_file *m, u32 *formats, size_t formats_count)
+{
+	for (int i = 0; i < formats_count; i++) {
+		seq_printf(m, "%p4cc", &formats[i]);
+		if (i != formats_count - 1)
+			seq_puts(m, ", ");
+	}
+}
+
 static int vkms_config_show(struct seq_file *m, void *data)
 {
 	struct drm_debugfs_entry *entry = m->private;
@@ -482,6 +527,10 @@ static int vkms_config_show(struct seq_file *m, void *data)
 		seq_puts(m, "\n");
 		seq_printf(m, "\tdefault color range=%s\n",
 			   drm_get_color_range_name(vkms_config_plane_get_default_color_range(plane_cfg)));
+		seq_puts(m, "\tsupported formats=");
+		show_formats(m, vkms_config_plane_get_supported_formats(plane_cfg),
+			     vkms_config_plane_get_supported_formats_count(plane_cfg));
+		seq_puts(m, "\n");
 	}
 
 	vkms_config_for_each_crtc(vkmsdev->config, crtc_cfg) {
@@ -520,6 +569,11 @@ struct vkms_config_plane *vkms_config_create_plane(struct vkms_config *config)
 	if (!plane_cfg)
 		return ERR_PTR(-ENOMEM);
 
+	if (vkms_config_plane_add_all_formats(plane_cfg)) {
+		kfree(plane_cfg);
+		return ERR_PTR(-ENOMEM);
+	}
+
 	plane_cfg->config = config;
 	plane_cfg->default_pipeline = false;
 	vkms_config_plane_set_type(plane_cfg, DRM_PLANE_TYPE_OVERLAY);
@@ -650,6 +704,76 @@ static struct vkms_config_plane *vkms_config_crtc_get_plane(const struct vkms_co
 	return NULL;
 }
 
+int __must_check vkms_config_plane_add_all_formats(struct vkms_config_plane *plane_cfg)
+{
+	u32 *ret = krealloc_array(plane_cfg->supported_formats,
+				  ARRAY_SIZE(vkms_supported_plane_formats),
+				  sizeof(uint32_t), GFP_KERNEL);
+	if (!ret)
+		return -ENOMEM;
+	plane_cfg->supported_formats = ret;
+
+	memcpy(plane_cfg->supported_formats, vkms_supported_plane_formats,
+	       sizeof(vkms_supported_plane_formats));
+	plane_cfg->supported_formats_count = ARRAY_SIZE(vkms_supported_plane_formats);
+	return 0;
+}
+
+static bool is_supported_format(u32 drm_format)
+{
+	for (int i = 0; i < ARRAY_SIZE(vkms_supported_plane_formats); i++) {
+		if (vkms_supported_plane_formats[i] == drm_format)
+			return true;
+	}
+
+	return false;
+}
+
+static bool vkms_config_plane_has_format(struct vkms_config_plane *plane_cfg, u32 drm_format)
+{
+	for (unsigned int i = 0; i < plane_cfg->supported_formats_count; i++) {
+		if (plane_cfg->supported_formats[i] == drm_format)
+			return true;
+	}
+	return false;
+}
+
+int __must_check vkms_config_plane_add_format(struct vkms_config_plane *plane_cfg, u32 drm_format)
+{
+	if (!is_supported_format(drm_format))
+		return -EINVAL;
+
+	if (vkms_config_plane_has_format(plane_cfg, drm_format))
+		return 0;
+
+	u32 *new_ptr = krealloc_array(plane_cfg->supported_formats,
+				      plane_cfg->supported_formats_count + 1,
+				      sizeof(*plane_cfg->supported_formats), GFP_KERNEL);
+	if (!new_ptr)
+		return -ENOMEM;
+
+	plane_cfg->supported_formats = new_ptr;
+	plane_cfg->supported_formats[plane_cfg->supported_formats_count] = drm_format;
+	plane_cfg->supported_formats_count++;
+
+	return 0;
+}
+
+void vkms_config_plane_remove_all_formats(struct vkms_config_plane *plane_cfg)
+{
+	plane_cfg->supported_formats_count = 0;
+}
+
+void vkms_config_plane_remove_format(struct vkms_config_plane *plane_cfg, u32 drm_format)
+{
+	for (unsigned int i = 0; i < plane_cfg->supported_formats_count; i++) {
+		if (plane_cfg->supported_formats[i] == drm_format) {
+			plane_cfg->supported_formats[i] = plane_cfg->supported_formats[plane_cfg->supported_formats_count - 1];
+			plane_cfg->supported_formats_count--;
+		}
+	}
+}
+
 struct vkms_config_plane *vkms_config_crtc_primary_plane(const struct vkms_config *config,
 							 struct vkms_config_crtc *crtc_cfg)
 {
diff --git a/drivers/gpu/drm/vkms/vkms_config.h b/drivers/gpu/drm/vkms/vkms_config.h
index bb2721a18d61..f268c3172217 100644
--- a/drivers/gpu/drm/vkms/vkms_config.h
+++ b/drivers/gpu/drm/vkms/vkms_config.h
@@ -49,6 +49,8 @@ struct vkms_config {
  * @supported_color_encodings: Color encodings that this plane will support
  * @default_color_range: Default color range that should be used by this plane
  * @supported_color_ranges: Color ranges that this plane will support
+ * @supported_formats: List of supported formats
+ * @supported_formats_count: Length of @supported_formats
  */
 struct vkms_config_plane {
 	struct list_head link;
@@ -62,6 +64,8 @@ struct vkms_config_plane {
 	unsigned int supported_color_encodings;
 	enum drm_color_range default_color_range;
 	unsigned int supported_color_ranges;
+	u32 *supported_formats;
+	unsigned int supported_formats_count;
 	struct xarray possible_crtcs;
 	bool default_pipeline;
 
@@ -474,6 +478,53 @@ bool vkms_config_valid_plane_color_range(const struct vkms_config *config,
 					 const struct vkms_config_plane *plane_cfg);
 #endif
 
+static inline u32 *
+vkms_config_plane_get_supported_formats(const struct vkms_config_plane *plane_cfg)
+{
+	return plane_cfg->supported_formats;
+}
+
+static inline unsigned int
+vkms_config_plane_get_supported_formats_count(struct vkms_config_plane *plane_cfg)
+{
+	return plane_cfg->supported_formats_count;
+}
+
+/** vkms_config_plane_add_format - Add a format to the list of supported format of a plane
+ *
+ * The passed drm_format can already be present in the list. This may fail if the allocation of a
+ * bigger array fails.
+ *
+ * @plane_cfg: Plane to add the format to
+ * @drm_format: Format to add to this plane
+ *
+ * Returns: 0 on success, -ENOMEM if array allocation fails, -EINVAL if the format is not supported
+ * by VKMS
+ */
+int __must_check vkms_config_plane_add_format(struct vkms_config_plane *plane_cfg, u32 drm_format);
+
+/**
+ * vkms_config_plane_add_all_formats - Helper to quickly add all the supported formats
+ * @plane_cfg: Plane to add the formats to
+ *
+ * Returns: 0 on success, -ENOMEM if array allocation fails, -EINVAL if the format is not supported
+ * by VKMS
+ */
+int __must_check vkms_config_plane_add_all_formats(struct vkms_config_plane *plane_cfg);
+
+/**
+ * vkms_config_plane_remove_format - Remove a specific format from a plane
+ * @plane_cfg: Plane to remove the format to
+ * @drm_format: Format to remove
+ */
+void vkms_config_plane_remove_format(struct vkms_config_plane *plane_cfg, u32 drm_format);
+
+/**
+ * vkms_config_plane_remove_all_formats - Remove all formats from a plane
+ * @plane_cfg: Plane to remove the formats from
+ */
+void vkms_config_plane_remove_all_formats(struct vkms_config_plane *plane_cfg);
+
 /**
  * vkms_config_plane_set_name() - Set the plane name
  * @plane_cfg: Plane to set the name to
diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
index 6461cf025a27..c2854b2117d1 100644
--- a/drivers/gpu/drm/vkms/vkms_plane.c
+++ b/drivers/gpu/drm/vkms/vkms_plane.c
@@ -15,42 +15,6 @@
 #include "vkms_drv.h"
 #include "vkms_formats.h"
 
-static const u32 vkms_formats[] = {
-	DRM_FORMAT_ARGB8888,
-	DRM_FORMAT_ABGR8888,
-	DRM_FORMAT_BGRA8888,
-	DRM_FORMAT_RGBA8888,
-	DRM_FORMAT_XRGB8888,
-	DRM_FORMAT_XBGR8888,
-	DRM_FORMAT_RGB888,
-	DRM_FORMAT_BGR888,
-	DRM_FORMAT_XRGB16161616,
-	DRM_FORMAT_XBGR16161616,
-	DRM_FORMAT_ARGB16161616,
-	DRM_FORMAT_ABGR16161616,
-	DRM_FORMAT_RGB565,
-	DRM_FORMAT_BGR565,
-	DRM_FORMAT_NV12,
-	DRM_FORMAT_NV16,
-	DRM_FORMAT_NV24,
-	DRM_FORMAT_NV21,
-	DRM_FORMAT_NV61,
-	DRM_FORMAT_NV42,
-	DRM_FORMAT_YUV420,
-	DRM_FORMAT_YUV422,
-	DRM_FORMAT_YUV444,
-	DRM_FORMAT_YVU420,
-	DRM_FORMAT_YVU422,
-	DRM_FORMAT_YVU444,
-	DRM_FORMAT_P010,
-	DRM_FORMAT_P012,
-	DRM_FORMAT_P016,
-	DRM_FORMAT_R1,
-	DRM_FORMAT_R2,
-	DRM_FORMAT_R4,
-	DRM_FORMAT_R8,
-};
-
 static struct drm_plane_state *
 vkms_plane_duplicate_state(struct drm_plane *plane)
 {
@@ -227,7 +191,8 @@ struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev,
 
 	plane = drmm_universal_plane_alloc(dev, struct vkms_plane, base, 0,
 					   &vkms_plane_funcs,
-					   vkms_formats, ARRAY_SIZE(vkms_formats),
+					   vkms_config_plane_get_supported_formats(plane_cfg),
+					   vkms_config_plane_get_supported_formats_count(plane_cfg),
 					   NULL, vkms_config_plane_get_type(plane_cfg),
 					   vkms_config_plane_get_name(plane_cfg));
 	if (IS_ERR(plane))

-- 
2.51.2

[PATCH v3 18/33] drm/vkms: Introduce configfs for plane format

[Louis Chauvet]

To allow the userspace to test many hardware configuration, introduce a
new interface to configure the available formats per planes. VKMS supports
multiple formats, so the userspace can choose any combination.

The supported formats are configured by writing the fourcc code in
supported_formats:
 # enable AR24 format
  echo '+AR24' > /config/vkms/DEVICE_1/planes/PLANE_1/supported_formats
 # disable AR24 format
  echo '-AR24' > /config/vkms/DEVICE_1/planes/PLANE_1/supported_formats
 # enable all format supported by VKMS
  echo '+*' > /config/vkms/DEVICE_1/planes/PLANE_1/supported_formats
 # disable all formats
  echo '-*' > /config/vkms/DEVICE_1/planes/PLANE_1/supported_formats

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 Documentation/ABI/testing/configfs-vkms         |   9 ++
 Documentation/gpu/vkms.rst                      |   7 +-
 drivers/gpu/drm/vkms/tests/Makefile             |   3 +-
 drivers/gpu/drm/vkms/tests/vkms_configfs_test.c | 102 ++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_configfs.c            | 118 ++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_configfs.h            |   6 ++
 6 files changed, 243 insertions(+), 2 deletions(-)

diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
index 2ace79ce848a..48f92538c602 100644
--- a/Documentation/ABI/testing/configfs-vkms
+++ b/Documentation/ABI/testing/configfs-vkms
@@ -153,6 +153,15 @@ Description:
         Default color range presented to userspace, same
         values as supported_color_ranges.
 
+What:		/sys/kernel/config/vkms/<device>/planes/<plane>/supported_formats
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        List of supported formats for this plane. To add a new
+        item, write its fourcc code prefixed with '+'. To remove,
+        use '-' prefix. Use '+*' to add all formats, '-*' to
+        remove all.
+
 What:		/sys/kernel/config/vkms/<device>/planes/<plane>/possible_crtcs
 Date:		Nov 2025
 Contact:	dri-devel@lists.freedesktop.org
diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index ab0eb2f97fc2..15d62ad963c9 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -87,7 +87,7 @@ Start by creating one or more planes::
 
   sudo mkdir /config/vkms/my-vkms/planes/plane0
 
-Planes have 8 configurable attributes:
+Planes have 9 configurable attributes:
 
 - type: Plane type: 0 overlay, 1 primary, 2 cursor (same values as those
   exposed by the "type" property of a plane)
@@ -109,6 +109,11 @@ Planes have 8 configurable attributes:
   must be set too.
 - default_color_range: Default color range presented to the userspace, same
   values as supported_color_ranges
+- supported_formats: List of supported formats for this plane. To add a new item in the
+  list, write it using a plus and fourcc code: +XR24
+  To remove a format, use a minus and its fourcc: -XR24
+  To add all formats use +*
+  To remove all formats, use -*
 
 Continue by creating one or more CRTCs::
 
diff --git a/drivers/gpu/drm/vkms/tests/Makefile b/drivers/gpu/drm/vkms/tests/Makefile
index d4d9ba8d4c54..92cfa7262ba4 100644
--- a/drivers/gpu/drm/vkms/tests/Makefile
+++ b/drivers/gpu/drm/vkms/tests/Makefile
@@ -3,6 +3,7 @@
 vkms-kunit-tests-y := \
 	vkms_config_test.o \
 	vkms_format_test.o \
-	vkms_color_test.o
+	vkms_color_test.o \
+	vkms_configfs_test.o \
 
 obj-$(CONFIG_DRM_VKMS_KUNIT_TEST) += vkms-kunit-tests.o
diff --git a/drivers/gpu/drm/vkms/tests/vkms_configfs_test.c b/drivers/gpu/drm/vkms/tests/vkms_configfs_test.c
new file mode 100644
index 000000000000..8d02c2c459d9
--- /dev/null
+++ b/drivers/gpu/drm/vkms/tests/vkms_configfs_test.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include "linux/printk.h"
+#include <kunit/test.h>
+
+#include "../vkms_configfs.h"
+
+MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING");
+
+/**
+ * struct vkms_configfs_parse_format_case - Store test case for format parsing
+ * @str: Contains the string to parse
+ * @str_len: str len
+ * @expected_len: expected len of the matched format
+ * @expected_offset: expected offset in the string for the parsed format
+ */
+struct vkms_configfs_parse_format_case {
+	const char *str;
+	int str_len;
+	int expected_len;
+	int expected_offset;
+};
+
+struct vkms_configfs_parse_format_case vkms_configfs_parse_format_test_cases[] = {
+	{
+		.str = "+RG24",
+		.str_len = 6,
+		.expected_len = 5,
+		.expected_offset = 0,
+	}, {
+		.str = "-RG24",
+		.str_len = 6,
+		.expected_len = 5,
+		.expected_offset = 0
+	}, {
+		.str = "  -RG24",
+		.str_len = 8,
+		.expected_len = 5,
+		.expected_offset = 2
+	}, {
+		.str = "+*",
+		.str_len = 3,
+		.expected_len = 2,
+		.expected_offset = 0
+	}, {
+		.str = "-RG24+RG24",
+		.str_len = 11,
+		.expected_len = 5,
+		.expected_offset = 0
+	}, {
+		.str = "-R1+RG24",
+		.str_len = 9,
+		.expected_len = 3,
+		.expected_offset = 0
+	}, {
+		.str = "\n-R1",
+		.str_len = 5,
+		.expected_len = 3,
+		.expected_offset = 1
+	}, {
+		.str = "-R1111",
+		.str_len = 3,
+		.expected_len = 3,
+		.expected_offset = 0
+	}
+};
+
+static void vkms_configfs_test_parse_format(struct kunit *test)
+{
+	const struct vkms_configfs_parse_format_case *param = test->param_value;
+	char *out;
+	int len = vkms_configfs_parse_next_format(param->str, param->str + param->str_len, &out);
+
+	KUNIT_EXPECT_EQ(test, len, param->expected_len);
+	KUNIT_EXPECT_PTR_EQ(test, out, param->str + param->expected_offset);
+}
+
+static void vkms_configfs_test_parse_format_get_desc(struct vkms_configfs_parse_format_case *t,
+						     char *desc)
+{
+	snprintf(desc, KUNIT_PARAM_DESC_SIZE, "%s", t->str);
+}
+
+KUNIT_ARRAY_PARAM(vkms_configfs_test_parse_format, vkms_configfs_parse_format_test_cases,
+		  vkms_configfs_test_parse_format_get_desc
+);
+
+static struct kunit_case vkms_configfs_test_cases[] = {
+	KUNIT_CASE_PARAM(vkms_configfs_test_parse_format,
+			 vkms_configfs_test_parse_format_gen_params),
+	{}
+};
+
+static struct kunit_suite vkms_configfs_test_suite = {
+	.name = "vkms-configfs",
+	.test_cases = vkms_configfs_test_cases,
+};
+
+kunit_test_suite(vkms_configfs_test_suite);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Kunit test for vkms configfs utility");
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index 7be6d10b2b68..a451d1122acf 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -3,6 +3,8 @@
 #include <linux/configfs.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
+#include <linux/string.h>
+#include <kunit/visibility.h>
 
 #include "vkms_drv.h"
 #include "vkms_config.h"
@@ -628,6 +630,120 @@ static ssize_t plane_default_color_encoding_store(struct config_item *item,
 	return count;
 }
 
+static ssize_t plane_supported_formats_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_plane *plane;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+
+	page[0] = '\0';
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		u32 *formats = vkms_config_plane_get_supported_formats(plane->config);
+
+		for (int i = 0;
+		     i < vkms_config_plane_get_supported_formats_count(plane->config);
+		     i++) {
+			char tmp[6] = { 0 };
+			const ssize_t ret = snprintf(tmp, ARRAY_SIZE(tmp), "%.*s\n",
+					       (int)sizeof(*formats),
+					       (char *)&formats[i]);
+			if (ret < 0)
+				return ret;
+			/*
+			 * Limitation of ConfigFS attributes, an attribute can't be bigger
+			 * than PAGE_SIZE. This will crop the result if this plane support
+			 * more than ≈1000 formats.
+			 */
+			if (ret + strlen(page) > PAGE_SIZE - 1)
+				return -ENOMEM;
+			strncat(page, tmp, ARRAY_SIZE(tmp));
+		}
+	}
+
+	return strlen(page);
+}
+
+/**
+ * parse_next_format() - Parse the next format in page, skipping all non fourcc-related characters
+ * @page: page to search into
+ * @page_end: last character of the page
+ * @out: Output pointer, will point inside page
+ *
+ * Returns: size of the matched format, @out will point to the + or -
+ */
+VISIBLE_IF_KUNIT
+int vkms_configfs_parse_next_format(const char *page, const char *page_end, char **out)
+{
+	int count = page - page_end;
+	char *tmp_plus = strnchr(page, count, '+');
+	char *tmp_minus = strnchr(page, count, '-');
+
+	if (!tmp_plus && !tmp_minus)
+		return 0;
+	if (!tmp_plus)
+		*out = tmp_minus;
+	else if (!tmp_minus)
+		*out = tmp_plus;
+	else
+		*out = min(tmp_plus, tmp_minus);
+
+	char *end = *out + 1;
+
+	while (end < page_end) {
+		if (!isalnum(*end) && *end != '*')
+			break;
+		end++;
+	}
+
+	return end - *out;
+}
+EXPORT_SYMBOL_IF_KUNIT(vkms_configfs_parse_next_format);
+
+static ssize_t plane_supported_formats_store(struct config_item *item,
+					     const char *page, size_t count)
+{
+	struct vkms_configfs_plane *plane;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+	int ret = 0;
+	const char *end_page = page + count;
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		while (1) {
+			char *tmp;
+			char fmt[4] = {' ', ' ', ' ', ' '};
+			int len = vkms_configfs_parse_next_format(page, end_page, &tmp);
+
+			// No fourcc code found
+			if (len <= 1 || len > 5)
+				break;
+
+			page = tmp + len;
+			memcpy(fmt, &tmp[1], min(len - 1, 4));
+			if (tmp[0] == '+') {
+				if (fmt[0] == '*') {
+					ret = vkms_config_plane_add_all_formats(plane->config);
+					if (ret)
+						return ret;
+				} else {
+					ret = vkms_config_plane_add_format(plane->config,
+									   *(int *)fmt);
+					if (ret)
+						return ret;
+				}
+			} else if (tmp[0] == '-') {
+				if (fmt[0] == '*')
+					vkms_config_plane_remove_all_formats(plane->config);
+				else
+					vkms_config_plane_remove_format(plane->config, *(int *)fmt);
+			}
+		}
+	}
+
+	return count;
+}
+
 CONFIGFS_ATTR(plane_, type);
 CONFIGFS_ATTR(plane_, name);
 CONFIGFS_ATTR(plane_, supported_rotations);
@@ -636,6 +752,7 @@ CONFIGFS_ATTR(plane_, supported_color_ranges);
 CONFIGFS_ATTR(plane_, default_color_range);
 CONFIGFS_ATTR(plane_, supported_color_encodings);
 CONFIGFS_ATTR(plane_, default_color_encoding);
+CONFIGFS_ATTR(plane_, supported_formats);
 
 static struct configfs_attribute *plane_item_attrs[] = {
 	&plane_attr_type,
@@ -646,6 +763,7 @@ static struct configfs_attribute *plane_item_attrs[] = {
 	&plane_attr_default_color_range,
 	&plane_attr_supported_color_encodings,
 	&plane_attr_default_color_encoding,
+	&plane_attr_supported_formats,
 	NULL,
 };
 
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.h b/drivers/gpu/drm/vkms/vkms_configfs.h
index e9020b0043db..2774655bfcc5 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.h
+++ b/drivers/gpu/drm/vkms/vkms_configfs.h
@@ -2,7 +2,13 @@
 #ifndef _VKMS_CONFIGFS_H_
 #define _VKMS_CONFIGFS_H_
 
+#include <linux/types.h>
+
 int vkms_configfs_register(void);
 void vkms_configfs_unregister(void);
 
+#if IS_ENABLED(CONFIG_KUNIT)
+int vkms_configfs_parse_next_format(const char *page, const char *end_page, char **out);
+#endif
+
 #endif /* _VKMS_CONFIGFS_H_ */

-- 
2.51.2

[PATCH v3 19/33] drm/vkms: Properly render plane using their zpos

[Louis Chauvet]

Currently planes are rendered in creation order. This is not an issue, but
with the introduction of new zpos configuration, it is required to
properly render planes.

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/vkms_crtc.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_crtc.c b/drivers/gpu/drm/vkms/vkms_crtc.c
index 9a7db1d51022..ae0d3356dceb 100644
--- a/drivers/gpu/drm/vkms/vkms_crtc.c
+++ b/drivers/gpu/drm/vkms/vkms_crtc.c
@@ -4,6 +4,7 @@
 
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
+#include <drm/drm_blend.h>
 #include <drm/drm_managed.h>
 #include <drm/drm_print.h>
 #include <drm/drm_probe_helper.h>
@@ -142,14 +143,20 @@ static int vkms_crtc_atomic_check(struct drm_crtc *crtc,
 		return -ENOMEM;
 	vkms_state->num_active_planes = i;
 
-	i = 0;
+	ret = drm_atomic_normalize_zpos(crtc->dev, state);
+	if (ret)
+		return ret;
+
 	drm_for_each_plane_mask(plane, crtc->dev, crtc_state->plane_mask) {
 		plane_state = drm_atomic_get_new_plane_state(crtc_state->state, plane);
 
 		if (!plane_state->visible)
 			continue;
 
-		vkms_state->active_planes[i++] =
+		// Order planes according to their normalized_zpos
+		// After drm_atomic_normalize_zpos, the possible values are 0..n_planes-1
+		// so store them using this index
+		vkms_state->active_planes[plane_state->normalized_zpos] =
 			to_vkms_plane_state(plane_state);
 	}
 

-- 
2.51.2

[PATCH v3 20/33] drm/vkms: Introduce config for plane zpos property

[Louis Chauvet]

VKMS can render plane in any order. Introduce the appropriate
configuration.

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/tests/vkms_config_test.c |  89 ++++++++++++++++
 drivers/gpu/drm/vkms/vkms_config.c            |  43 ++++++++
 drivers/gpu/drm/vkms/vkms_config.h            | 143 ++++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_plane.c             |  10 ++
 4 files changed, 285 insertions(+)

diff --git a/drivers/gpu/drm/vkms/tests/vkms_config_test.c b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
index a88d8b4a969e..4a5899b8ccfd 100644
--- a/drivers/gpu/drm/vkms/tests/vkms_config_test.c
+++ b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
@@ -201,6 +201,9 @@ static void vkms_config_test_default_config(struct kunit *test)
 		KUNIT_EXPECT_EQ(test,
 				vkms_config_plane_get_default_color_encoding(plane_cfg),
 				DRM_COLOR_YCBCR_BT601);
+		KUNIT_EXPECT_EQ(test, vkms_config_plane_get_zpos_enabled(plane_cfg), false);
+		// No need to test the other zpos configurations as they are discarded if
+		// the zpos property is not created.
 	}
 
 	/* Encoders */
@@ -619,6 +622,91 @@ static void vkms_config_test_valid_plane_color_range(struct kunit *test)
 	vkms_config_destroy(config);
 }
 
+static void vkms_config_test_valid_plane_zpos(struct kunit *test)
+{
+	struct vkms_config *config;
+	struct vkms_config_plane *plane_cfg;
+
+	config = vkms_config_default_create(false, false, false, false);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, config);
+
+	plane_cfg = get_first_plane(config);
+
+	/* Valid, zpos disabled */
+	vkms_config_plane_set_zpos_enabled(plane_cfg, false);
+	vkms_config_plane_set_zpos_mutable(plane_cfg, false);
+	vkms_config_plane_set_zpos_initial(plane_cfg, 0);
+	vkms_config_plane_set_zpos_min(plane_cfg, 0);
+	vkms_config_plane_set_zpos_max(plane_cfg, 0);
+	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
+
+	/* Valid, zpos disabled, min/max are ignored */
+	vkms_config_plane_set_zpos_enabled(plane_cfg, false);
+	vkms_config_plane_set_zpos_mutable(plane_cfg, false);
+	vkms_config_plane_set_zpos_initial(plane_cfg, 8);
+	vkms_config_plane_set_zpos_min(plane_cfg, 3);
+	vkms_config_plane_set_zpos_max(plane_cfg, 2);
+	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
+
+	/* Valid, zpos enabled but mutable disabled */
+	vkms_config_plane_set_zpos_enabled(plane_cfg, true);
+	vkms_config_plane_set_zpos_mutable(plane_cfg, false);
+	vkms_config_plane_set_zpos_initial(plane_cfg, 1);
+	vkms_config_plane_set_zpos_min(plane_cfg, 0);
+	vkms_config_plane_set_zpos_max(plane_cfg, 0);
+	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
+
+	/* Valid, zpos enabled but mutable disabled */
+	vkms_config_plane_set_zpos_enabled(plane_cfg, true);
+	vkms_config_plane_set_zpos_mutable(plane_cfg, false);
+	vkms_config_plane_set_zpos_initial(plane_cfg, 0);
+	vkms_config_plane_set_zpos_min(plane_cfg, 0);
+	vkms_config_plane_set_zpos_max(plane_cfg, 0);
+	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
+
+	/* Invalid, zpos enabled with min > max */
+	vkms_config_plane_set_zpos_enabled(plane_cfg, true);
+	vkms_config_plane_set_zpos_mutable(plane_cfg, true);
+	vkms_config_plane_set_zpos_initial(plane_cfg, 0);
+	vkms_config_plane_set_zpos_min(plane_cfg, 1);
+	vkms_config_plane_set_zpos_max(plane_cfg, 0);
+	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
+
+	/* Valid, zpos enabled with min <= max */
+	vkms_config_plane_set_zpos_enabled(plane_cfg, true);
+	vkms_config_plane_set_zpos_mutable(plane_cfg, true);
+	vkms_config_plane_set_zpos_initial(plane_cfg, 0);
+	vkms_config_plane_set_zpos_min(plane_cfg, 0);
+	vkms_config_plane_set_zpos_max(plane_cfg, 1);
+	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
+
+	/* Invalid, zpos enabled with initial < min */
+	vkms_config_plane_set_zpos_enabled(plane_cfg, true);
+	vkms_config_plane_set_zpos_mutable(plane_cfg, true);
+	vkms_config_plane_set_zpos_initial(plane_cfg, 0);
+	vkms_config_plane_set_zpos_min(plane_cfg, 1);
+	vkms_config_plane_set_zpos_max(plane_cfg, 2);
+	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
+
+	/* Invalid, zpos enabled with initial > max */
+	vkms_config_plane_set_zpos_enabled(plane_cfg, true);
+	vkms_config_plane_set_zpos_mutable(plane_cfg, true);
+	vkms_config_plane_set_zpos_initial(plane_cfg, 3);
+	vkms_config_plane_set_zpos_min(plane_cfg, 1);
+	vkms_config_plane_set_zpos_max(plane_cfg, 2);
+	KUNIT_EXPECT_FALSE(test, vkms_config_is_valid(config));
+
+	/* Valid, zpos enabled with initial between min and max */
+	vkms_config_plane_set_zpos_enabled(plane_cfg, true);
+	vkms_config_plane_set_zpos_mutable(plane_cfg, true);
+	vkms_config_plane_set_zpos_initial(plane_cfg, 1);
+	vkms_config_plane_set_zpos_min(plane_cfg, 0);
+	vkms_config_plane_set_zpos_max(plane_cfg, 2);
+	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
+
+	vkms_config_destroy(config);
+}
+
 static void vkms_config_test_valid_plane_possible_crtcs(struct kunit *test)
 {
 	struct vkms_config *config;
@@ -1144,6 +1232,7 @@ static struct kunit_case vkms_config_test_cases[] = {
 	KUNIT_CASE(vkms_config_test_valid_plane_rotations),
 	KUNIT_CASE(vkms_config_test_valid_plane_color_encoding),
 	KUNIT_CASE(vkms_config_test_valid_plane_color_range),
+	KUNIT_CASE(vkms_config_test_valid_plane_zpos),
 	KUNIT_CASE(vkms_config_test_valid_plane_possible_crtcs),
 	KUNIT_CASE(vkms_config_test_invalid_crtc_number),
 	KUNIT_CASE(vkms_config_test_invalid_encoder_number),
diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
index 1c97f952bf9e..415556952b6f 100644
--- a/drivers/gpu/drm/vkms/vkms_config.c
+++ b/drivers/gpu/drm/vkms/vkms_config.c
@@ -91,6 +91,7 @@ struct vkms_config *vkms_config_default_create(bool enable_cursor,
 	if (IS_ERR(plane_cfg))
 		goto err_alloc;
 	vkms_config_plane_set_type(plane_cfg, DRM_PLANE_TYPE_PRIMARY);
+	vkms_config_plane_set_zpos_enabled(plane_cfg, false);
 
 	crtc_cfg = vkms_config_create_crtc(config);
 	if (IS_ERR(crtc_cfg))
@@ -110,6 +111,7 @@ struct vkms_config *vkms_config_default_create(bool enable_cursor,
 			vkms_config_plane_set_type(plane_cfg,
 						   DRM_PLANE_TYPE_OVERLAY);
 			vkms_config_plane_set_default_pipeline(plane_cfg, enable_plane_pipeline);
+			vkms_config_plane_set_zpos_enabled(plane_cfg, false);
 
 			if (vkms_config_plane_attach_crtc(plane_cfg, crtc_cfg))
 				goto err_alloc;
@@ -123,6 +125,7 @@ struct vkms_config *vkms_config_default_create(bool enable_cursor,
 
 		vkms_config_plane_set_type(plane_cfg, DRM_PLANE_TYPE_CURSOR);
 		vkms_config_plane_set_default_pipeline(plane_cfg, enable_plane_pipeline);
+		vkms_config_plane_set_zpos_enabled(plane_cfg, false);
 
 		if (vkms_config_plane_attach_crtc(plane_cfg, crtc_cfg))
 			goto err_alloc;
@@ -253,6 +256,33 @@ bool vkms_config_valid_plane_color_range(const struct vkms_config *config,
 }
 EXPORT_SYMBOL_IF_KUNIT(vkms_config_valid_plane_color_range);
 
+VISIBLE_IF_KUNIT
+bool vkms_config_valid_plane_zpos(const struct vkms_config *config,
+				  const struct vkms_config_plane *plane_cfg)
+{
+	struct drm_device *dev = config->dev ? &config->dev->drm : NULL;
+
+	if (!vkms_config_plane_get_zpos_enabled(plane_cfg) ||
+	    !vkms_config_plane_get_zpos_mutable(plane_cfg))
+		return true;
+
+	if (vkms_config_plane_get_zpos_initial(plane_cfg) >
+	    vkms_config_plane_get_zpos_max(plane_cfg)) {
+		drm_info(dev, "Configured initial zpos value bigger than zpos max\n");
+		return false;
+	}
+
+	if (vkms_config_plane_get_zpos_max(plane_cfg) <
+	    vkms_config_plane_get_zpos_min(plane_cfg) ||
+	    vkms_config_plane_get_zpos_initial(plane_cfg) <
+	    vkms_config_plane_get_zpos_min(plane_cfg)) {
+		drm_info(dev, "Configured zpos value outside (zpos min; zpos max)\n");
+		return false;
+	}
+
+	return true;
+}
+
 static bool valid_planes_for_crtc(const struct vkms_config *config,
 				  struct vkms_config_crtc *crtc_cfg)
 {
@@ -429,6 +459,9 @@ bool vkms_config_is_valid(const struct vkms_config *config)
 				 "Both supported color encodings and color ranges must be set, or none\n");
 			return false;
 		}
+
+		if (!vkms_config_valid_plane_zpos(config, plane_cfg))
+			return false;
 	}
 
 	if (!valid_plane_number(config))
@@ -531,6 +564,16 @@ static int vkms_config_show(struct seq_file *m, void *data)
 		show_formats(m, vkms_config_plane_get_supported_formats(plane_cfg),
 			     vkms_config_plane_get_supported_formats_count(plane_cfg));
 		seq_puts(m, "\n");
+		seq_printf(m, "\tzpos_enabled=%s\n",
+			   str_true_false(vkms_config_plane_get_zpos_enabled(plane_cfg)));
+		seq_printf(m, "\tzpos_mutable=%s\n",
+			   str_true_false(vkms_config_plane_get_zpos_mutable(plane_cfg)));
+		seq_printf(m, "\tzpos_min=%d\n",
+			   vkms_config_plane_get_zpos_min(plane_cfg));
+		seq_printf(m, "\tzpos_initial=%d\n",
+			   vkms_config_plane_get_zpos_initial(plane_cfg));
+		seq_printf(m, "\tzpos_max=%d\n",
+			   vkms_config_plane_get_zpos_max(plane_cfg));
 	}
 
 	vkms_config_for_each_crtc(vkmsdev->config, crtc_cfg) {
diff --git a/drivers/gpu/drm/vkms/vkms_config.h b/drivers/gpu/drm/vkms/vkms_config.h
index f268c3172217..9217097c0296 100644
--- a/drivers/gpu/drm/vkms/vkms_config.h
+++ b/drivers/gpu/drm/vkms/vkms_config.h
@@ -51,6 +51,11 @@ struct vkms_config {
  * @supported_color_ranges: Color ranges that this plane will support
  * @supported_formats: List of supported formats
  * @supported_formats_count: Length of @supported_formats
+ * @zpos_enabled: Enable or disable the zpos property
+ * @zpos_mutable: Make the zpos property mutable or not (ignored if @zpos_enabled is false)
+ * @zpos_initial: Initial value for zpos property (ignored if @zpos_enabled is false)
+ * @zpos_min: Minimal value for zpos property (ignored if @zpos_enabled is false)
+ * @zpos_max: Maximal value for zpos property (ignored if @zpos_enabled is false)
  */
 struct vkms_config_plane {
 	struct list_head link;
@@ -68,6 +73,11 @@ struct vkms_config_plane {
 	unsigned int supported_formats_count;
 	struct xarray possible_crtcs;
 	bool default_pipeline;
+	bool zpos_enabled;
+	bool zpos_mutable;
+	unsigned int zpos_initial;
+	unsigned int zpos_min;
+	unsigned int zpos_max;
 
 	/* Internal usage */
 	struct vkms_plane *plane;
@@ -549,6 +559,139 @@ vkms_config_plane_get_name(const struct vkms_config_plane *plane_cfg)
 	return plane_cfg->name;
 }
 
+/**
+ * vkms_config_plane_set_zpos_enabled() - Enable or disable zpos property for a plane
+ * @plane_cfg: Plane configuration to modify
+ * @zpos_enabled: Whether to enable the zpos property
+ */
+static inline
+void vkms_config_plane_set_zpos_enabled(struct vkms_config_plane *plane_cfg,
+					bool zpos_enabled)
+{
+	plane_cfg->zpos_enabled = zpos_enabled;
+}
+
+/**
+ * vkms_config_plane_set_zpos_mutable() - Set whether zpos property is mutable
+ * @plane_cfg: Plane configuration to modify
+ * @zpos_mutable: Whether the zpos property should be mutable
+ */
+static inline
+void vkms_config_plane_set_zpos_mutable(struct vkms_config_plane *plane_cfg,
+					bool zpos_mutable)
+{
+	plane_cfg->zpos_mutable = zpos_mutable;
+}
+
+/**
+ * vkms_config_plane_set_zpos_initial() - Set the initial zpos value
+ * @plane_cfg: Plane configuration to modify
+ * @zpos_initial: Initial zpos value
+ */
+static inline
+void vkms_config_plane_set_zpos_initial(struct vkms_config_plane *plane_cfg,
+					unsigned int zpos_initial)
+{
+	plane_cfg->zpos_initial = zpos_initial;
+}
+
+/**
+ * vkms_config_plane_set_zpos_min() - Set the minimum zpos value
+ * @plane_cfg: Plane configuration to modify
+ * @zpos_min: Minimum zpos value
+ */
+static inline
+void vkms_config_plane_set_zpos_min(struct vkms_config_plane *plane_cfg,
+				    unsigned int zpos_min)
+{
+	plane_cfg->zpos_min = zpos_min;
+}
+
+/**
+ * vkms_config_plane_set_zpos_max() - Set the maximum zpos value
+ * @plane_cfg: Plane configuration to modify
+ * @zpos_max: Maximum zpos value
+ */
+static inline
+void vkms_config_plane_set_zpos_max(struct vkms_config_plane *plane_cfg,
+				    unsigned int zpos_max)
+{
+	plane_cfg->zpos_max = zpos_max;
+}
+
+/**
+ * vkms_config_plane_get_zpos_enabled() - Check if zpos property is enabled
+ * @plane_cfg: Plane configuration to check
+ *
+ * Returns:
+ * True if the zpos property is enabled for this plane, false otherwise.
+ */
+static inline
+bool vkms_config_plane_get_zpos_enabled(const struct vkms_config_plane *plane_cfg)
+{
+	return plane_cfg->zpos_enabled;
+}
+
+/**
+ * vkms_config_plane_get_zpos_mutable() - Check if zpos property is mutable
+ * @plane_cfg: Plane configuration to check
+ *
+ * Returns:
+ * True if the zpos property is mutable for this plane, false otherwise.
+ */
+static inline
+bool vkms_config_plane_get_zpos_mutable(const struct vkms_config_plane *plane_cfg)
+{
+	return plane_cfg->zpos_mutable;
+}
+
+/**
+ * vkms_config_plane_get_zpos_initial() - Get the initial zpos value
+ * @plane_cfg: Plane configuration to check
+ *
+ * Returns:
+ * The initial zpos value for this plane. The return value is undefined if
+ * zpos is disabled.
+ */
+static inline
+unsigned int vkms_config_plane_get_zpos_initial(const struct vkms_config_plane *plane_cfg)
+{
+	return plane_cfg->zpos_initial;
+}
+
+/**
+ * vkms_config_plane_get_zpos_min() - Get the minimum zpos value
+ * @plane_cfg: Plane configuration to check
+ *
+ * Returns:
+ * The minimum allowed zpos value for this plane. The return value is undefined
+ * if zpos is disabled.
+ */
+static inline
+unsigned int vkms_config_plane_get_zpos_min(const struct vkms_config_plane *plane_cfg)
+{
+	return plane_cfg->zpos_min;
+}
+
+/**
+ * vkms_config_plane_get_zpos_max() - Get the maximum zpos value
+ * @plane_cfg: Plane configuration to check
+ *
+ * Returns:
+ * The maximum allowed zpos value for this plane. The return value is undefined
+ * if zpos is disabled.
+ */
+static inline
+unsigned int vkms_config_plane_get_zpos_max(const struct vkms_config_plane *plane_cfg)
+{
+	return plane_cfg->zpos_max;
+}
+
+#if IS_ENABLED(CONFIG_KUNIT)
+bool vkms_config_valid_plane_zpos(const struct vkms_config *config,
+				  const struct vkms_config_plane *plane_cfg);
+#endif
+
 /**
  * vkms_config_plane_attach_crtc - Attach a plane to a CRTC
  * @plane_cfg: Plane to attach
diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
index c2854b2117d1..809ca07e5f69 100644
--- a/drivers/gpu/drm/vkms/vkms_plane.c
+++ b/drivers/gpu/drm/vkms/vkms_plane.c
@@ -214,6 +214,16 @@ struct vkms_plane *vkms_plane_init(struct vkms_device *vkmsdev,
 
 	if (vkms_config_plane_get_default_pipeline(plane_cfg))
 		vkms_initialize_colorops(&plane->base);
+	if (vkms_config_plane_get_zpos_enabled(plane_cfg)) {
+		if (vkms_config_plane_get_zpos_mutable(plane_cfg))
+			drm_plane_create_zpos_property(&plane->base,
+						       vkms_config_plane_get_zpos_initial(plane_cfg),
+						       vkms_config_plane_get_zpos_min(plane_cfg),
+						       vkms_config_plane_get_zpos_max(plane_cfg));
+		else
+			drm_plane_create_zpos_immutable_property(&plane->base,
+								 vkms_config_plane_get_zpos_initial(plane_cfg));
+	}
 
 	return plane;
 }

-- 
2.51.2

[PATCH v3 21/33] drm/vkms: Introduce configfs for plane zpos property

[Louis Chauvet]

Modern compositor rely on zpos management to offload some processing to
deticated hardware. In order to test multiple configurations, add zpos
configuration to configFS.

Introduce multiple attributes to configure zpos:
- zpos_enabled - Create or not the zpos property. If not created, the zpos
  is undefined.
- zpos_mutable - If the zpos property is created, allow or not the
  userspace to modify it
- zpos_initial - Initial value for zpos property. Must be between zpos_min
  and zpos_max
- zpos_min - Minimum zpos value for this plane. Must be <= zpos_max
- zpos_max - Maximum zpos value for this plane. Must be >= zpos_min

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 Documentation/ABI/testing/configfs-vkms |  36 +++++++
 Documentation/gpu/vkms.rst              |   9 +-
 drivers/gpu/drm/vkms/vkms_configfs.c    | 180 ++++++++++++++++++++++++++++++++
 3 files changed, 224 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
index 48f92538c602..34cb6aeec411 100644
--- a/Documentation/ABI/testing/configfs-vkms
+++ b/Documentation/ABI/testing/configfs-vkms
@@ -162,6 +162,42 @@ Description:
         use '-' prefix. Use '+*' to add all formats, '-*' to
         remove all.
 
+What:		/sys/kernel/config/vkms/<device>/planes/<plane>/zpos_enabled
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        Enable or disable the zpos property. Value: 1 - enabled,
+        0 - disabled.
+
+What:		/sys/kernel/config/vkms/<device>/planes/<plane>/zpos_mutable
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        Create the zpos property as mutable or immutable.
+        Value: 1 - mutable, 0 - immutable. No effect if
+        zpos_enabled is not set.
+
+What:		/sys/kernel/config/vkms/<device>/planes/<plane>/zpos_initial
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        Set the initial zpos value. Must be between zpos_min
+        and zpos_max. No effect if zpos_enabled is not set.
+
+What:		/sys/kernel/config/vkms/<device>/planes/<plane>/zpos_min
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        Set the minimal zpos value. No effect if zpos_enabled
+        is not set.
+
+What:		/sys/kernel/config/vkms/<device>/planes/<plane>/zpos_max
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        Set the maximal zpos value. No effect if zpos_enabled
+        is not set.
+
 What:		/sys/kernel/config/vkms/<device>/planes/<plane>/possible_crtcs
 Date:		Nov 2025
 Contact:	dri-devel@lists.freedesktop.org
diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index 15d62ad963c9..791c4f33a90a 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -87,7 +87,7 @@ Start by creating one or more planes::
 
   sudo mkdir /config/vkms/my-vkms/planes/plane0
 
-Planes have 9 configurable attributes:
+Planes have 14 configurable attributes:
 
 - type: Plane type: 0 overlay, 1 primary, 2 cursor (same values as those
   exposed by the "type" property of a plane)
@@ -114,6 +114,13 @@ Planes have 9 configurable attributes:
   To remove a format, use a minus and its fourcc: -XR24
   To add all formats use +*
   To remove all formats, use -*
+- zpos_enabled: Enable or not the zpos property: 1 enable, 0 disable
+- zpos_mutable: Create the zpos property as a mutable or imutable property: 1 mutable,
+  0 immutable. No effect if zpos_enabled is not set.
+- zpos_initial: Set the initial zpos value. Must be between zpos_min and zpos_max. No
+  effect if zpos_enabled is not set.
+- zpos_min: Set the minimum zpos value. No effect if zpos_enabled is not set.
+- zpos_max: Set the maximum zpos value. No effect if zpos_enabled is not set.
 
 Continue by creating one or more CRTCs::
 
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index a451d1122acf..e7f3ab54b5a1 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -744,6 +744,176 @@ static ssize_t plane_supported_formats_store(struct config_item *item,
 	return count;
 }
 
+static ssize_t plane_zpos_enabled_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_plane *plane;
+	bool enabled;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+
+	scoped_guard(mutex, &plane->dev->lock)
+		enabled = vkms_config_plane_get_zpos_enabled(plane->config);
+
+	return sprintf(page, "%d\n", enabled);
+}
+
+static ssize_t plane_zpos_enabled_store(struct config_item *item, const char *page,
+					size_t count)
+{
+	struct vkms_configfs_plane *plane;
+	bool enabled;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+
+	if (kstrtobool(page, &enabled))
+		return -EINVAL;
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		if (plane->dev->enabled)
+			return -EBUSY;
+
+		vkms_config_plane_set_zpos_enabled(plane->config, enabled);
+	}
+
+	return (ssize_t)count;
+}
+
+static ssize_t plane_zpos_mutable_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_plane *plane;
+	bool mutable;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+
+	scoped_guard(mutex, &plane->dev->lock)
+		mutable = vkms_config_plane_get_zpos_mutable(plane->config);
+
+	return sprintf(page, "%d\n", mutable);
+}
+
+static ssize_t plane_zpos_mutable_store(struct config_item *item, const char *page,
+					size_t count)
+{
+	struct vkms_configfs_plane *plane;
+	bool mutable;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+
+	if (kstrtobool(page, &mutable))
+		return -EINVAL;
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		if (plane->dev->enabled)
+			return -EBUSY;
+
+		vkms_config_plane_set_zpos_mutable(plane->config, mutable);
+	}
+
+	return (ssize_t)count;
+}
+
+static ssize_t plane_zpos_initial_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_plane *plane;
+	unsigned int initial;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+
+	scoped_guard(mutex, &plane->dev->lock)
+		initial = vkms_config_plane_get_zpos_initial(plane->config);
+
+	return sprintf(page, "%u\n", initial);
+}
+
+static ssize_t plane_zpos_initial_store(struct config_item *item, const char *page,
+					size_t count)
+{
+	struct vkms_configfs_plane *plane;
+	unsigned int initial;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+
+	if (kstrtouint(page, 10, &initial))
+		return -EINVAL;
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		if (plane->dev->enabled)
+			return -EBUSY;
+
+		vkms_config_plane_set_zpos_initial(plane->config, initial);
+	}
+
+	return (ssize_t)count;
+}
+
+static ssize_t plane_zpos_min_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_plane *plane;
+	unsigned int min;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+
+	scoped_guard(mutex, &plane->dev->lock)
+		min = vkms_config_plane_get_zpos_min(plane->config);
+
+	return sprintf(page, "%u\n", min);
+}
+
+static ssize_t plane_zpos_min_store(struct config_item *item, const char *page,
+				    size_t count)
+{
+	struct vkms_configfs_plane *plane;
+	unsigned int min;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+
+	if (kstrtouint(page, 10, &min))
+		return -EINVAL;
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		if (plane->dev->enabled)
+			return -EBUSY;
+
+		vkms_config_plane_set_zpos_min(plane->config, min);
+	}
+
+	return (ssize_t)count;
+}
+
+static ssize_t plane_zpos_max_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_plane *plane;
+	unsigned int max;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+
+	scoped_guard(mutex, &plane->dev->lock)
+		max = vkms_config_plane_get_zpos_max(plane->config);
+
+	return sprintf(page, "%u\n", max);
+}
+
+static ssize_t plane_zpos_max_store(struct config_item *item, const char *page,
+				    size_t count)
+{
+	struct vkms_configfs_plane *plane;
+	unsigned int max;
+
+	plane = plane_item_to_vkms_configfs_plane(item);
+
+	if (kstrtouint(page, 10, &max))
+		return -EINVAL;
+
+	scoped_guard(mutex, &plane->dev->lock) {
+		if (plane->dev->enabled)
+			return -EBUSY;
+
+		vkms_config_plane_set_zpos_max(plane->config, max);
+	}
+
+	return (ssize_t)count;
+}
+
 CONFIGFS_ATTR(plane_, type);
 CONFIGFS_ATTR(plane_, name);
 CONFIGFS_ATTR(plane_, supported_rotations);
@@ -753,6 +923,11 @@ CONFIGFS_ATTR(plane_, default_color_range);
 CONFIGFS_ATTR(plane_, supported_color_encodings);
 CONFIGFS_ATTR(plane_, default_color_encoding);
 CONFIGFS_ATTR(plane_, supported_formats);
+CONFIGFS_ATTR(plane_, zpos_enabled);
+CONFIGFS_ATTR(plane_, zpos_mutable);
+CONFIGFS_ATTR(plane_, zpos_initial);
+CONFIGFS_ATTR(plane_, zpos_min);
+CONFIGFS_ATTR(plane_, zpos_max);
 
 static struct configfs_attribute *plane_item_attrs[] = {
 	&plane_attr_type,
@@ -764,6 +939,11 @@ static struct configfs_attribute *plane_item_attrs[] = {
 	&plane_attr_supported_color_encodings,
 	&plane_attr_default_color_encoding,
 	&plane_attr_supported_formats,
+	&plane_attr_zpos_enabled,
+	&plane_attr_zpos_mutable,
+	&plane_attr_zpos_initial,
+	&plane_attr_zpos_min,
+	&plane_attr_zpos_max,
 	NULL,
 };
 

-- 
2.51.2

[PATCH v3 22/33] drm/vkms: Introduce config for connector type

[Louis Chauvet]

In order to emulate connector-specific behavior, add connector type
configuration.

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/tests/vkms_config_test.c |  5 +++++
 drivers/gpu/drm/vkms/vkms_config.c            |  3 +++
 drivers/gpu/drm/vkms/vkms_config.h            | 24 ++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_connector.c         |  5 +++--
 drivers/gpu/drm/vkms/vkms_connector.h         |  4 +++-
 drivers/gpu/drm/vkms/vkms_output.c            |  2 +-
 6 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/vkms/tests/vkms_config_test.c b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
index 4a5899b8ccfd..1900cc79db2b 100644
--- a/drivers/gpu/drm/vkms/tests/vkms_config_test.c
+++ b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
@@ -137,6 +137,7 @@ static void vkms_config_test_default_config(struct kunit *test)
 	struct vkms_config *config;
 	struct vkms_config_plane *plane_cfg;
 	struct vkms_config_crtc *crtc_cfg;
+	struct vkms_config_connector *connector_cfg;
 	int n_primaries = 0;
 	int n_cursors = 0;
 	int n_overlays = 0;
@@ -211,6 +212,10 @@ static void vkms_config_test_default_config(struct kunit *test)
 
 	/* Connectors */
 	KUNIT_EXPECT_EQ(test, vkms_config_get_num_connectors(config), 1);
+	vkms_config_for_each_connector(config, connector_cfg) {
+		KUNIT_EXPECT_EQ(test, vkms_config_connector_get_type(connector_cfg),
+				DRM_MODE_CONNECTOR_VIRTUAL);
+	}
 
 	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
 
diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
index 415556952b6f..59ce55efb167 100644
--- a/drivers/gpu/drm/vkms/vkms_config.c
+++ b/drivers/gpu/drm/vkms/vkms_config.c
@@ -589,6 +589,8 @@ static int vkms_config_show(struct seq_file *m, void *data)
 		seq_puts(m, "connector:\n");
 		seq_printf(m, "\tstatus=%s\n",
 			   drm_get_connector_status_name(vkms_config_connector_get_status(connector_cfg)));
+		seq_printf(m, "\ttype=%s\n",
+			   drm_get_connector_type_name(vkms_config_connector_get_type(connector_cfg)));
 	}
 
 	return 0;
@@ -905,6 +907,7 @@ struct vkms_config_connector *vkms_config_create_connector(struct vkms_config *c
 
 	connector_cfg->config = config;
 	connector_cfg->status = connector_status_connected;
+	vkms_config_connector_set_type(connector_cfg, DRM_MODE_CONNECTOR_VIRTUAL);
 	xa_init_flags(&connector_cfg->possible_encoders, XA_FLAGS_ALLOC);
 
 	list_add_tail(&connector_cfg->link, &config->connectors);
diff --git a/drivers/gpu/drm/vkms/vkms_config.h b/drivers/gpu/drm/vkms/vkms_config.h
index 9217097c0296..4a4058b407e7 100644
--- a/drivers/gpu/drm/vkms/vkms_config.h
+++ b/drivers/gpu/drm/vkms/vkms_config.h
@@ -129,6 +129,7 @@ struct vkms_config_encoder {
  * struct vkms_config_connector
  *
  * @link: Link to the others connector in vkms_config
+ * @type: Store the type of connector using DRM_MODE_CONNECTOR_* values
  * @config: The vkms_config this connector belongs to
  * @status: Status (connected, disconnected...) of the connector
  * @possible_encoders: Array of encoders that can be used with this connector
@@ -141,6 +142,7 @@ struct vkms_config_connector {
 	struct list_head link;
 	struct vkms_config *config;
 
+	int type;
 	enum drm_connector_status status;
 	struct xarray possible_encoders;
 
@@ -343,6 +345,28 @@ vkms_config_plane_set_default_pipeline(struct vkms_config_plane *plane_cfg,
 }
 
 /**
+ * vkms_config_connector_get_type() - Return the connector type
+ * @connector_cfg: Connector to get the type from
+ */
+static inline int
+vkms_config_connector_get_type(const struct vkms_config_connector *connector_cfg)
+{
+	return connector_cfg->type;
+}
+
+/**
+ * vkms_config_connector_set_type() - Set the connector type
+ * @connector_cfg: Connector to set the type to
+ * @type: New connector type
+ */
+static inline void
+vkms_config_connector_set_type(struct vkms_config_connector *connector_cfg,
+			       int type)
+{
+	connector_cfg->type = type;
+}
+
+/*
  * vkms_config_plane_get_default_rotation() - Get the default rotation for a plane
  * @plane_cfg: Plane to get the default rotation from
  *
diff --git a/drivers/gpu/drm/vkms/vkms_connector.c b/drivers/gpu/drm/vkms/vkms_connector.c
index b0a6b212d3f4..5a87dc2d4c63 100644
--- a/drivers/gpu/drm/vkms/vkms_connector.c
+++ b/drivers/gpu/drm/vkms/vkms_connector.c
@@ -68,7 +68,8 @@ static const struct drm_connector_helper_funcs vkms_conn_helper_funcs = {
 	.best_encoder = vkms_conn_best_encoder,
 };
 
-struct vkms_connector *vkms_connector_init(struct vkms_device *vkmsdev)
+struct vkms_connector *vkms_connector_init(struct vkms_device *vkmsdev,
+					   struct vkms_config_connector *connector_cfg)
 {
 	struct drm_device *dev = &vkmsdev->drm;
 	struct vkms_connector *connector;
@@ -79,7 +80,7 @@ struct vkms_connector *vkms_connector_init(struct vkms_device *vkmsdev)
 		return ERR_PTR(-ENOMEM);
 
 	ret = drmm_connector_init(dev, &connector->base, &vkms_connector_funcs,
-				  DRM_MODE_CONNECTOR_VIRTUAL, NULL);
+				  vkms_config_connector_get_type(connector_cfg), NULL);
 	if (ret)
 		return ERR_PTR(ret);
 
diff --git a/drivers/gpu/drm/vkms/vkms_connector.h b/drivers/gpu/drm/vkms/vkms_connector.h
index ed312f4eff3a..33253d29b1cc 100644
--- a/drivers/gpu/drm/vkms/vkms_connector.h
+++ b/drivers/gpu/drm/vkms/vkms_connector.h
@@ -4,6 +4,7 @@
 #define _VKMS_CONNECTOR_H_
 
 #include "vkms_drv.h"
+#include "vkms_config.h"
 
 #define drm_connector_to_vkms_connector(target) \
 	container_of(target, struct vkms_connector, base)
@@ -24,7 +25,8 @@ struct vkms_connector {
  * Returns:
  * The connector or an error on failure.
  */
-struct vkms_connector *vkms_connector_init(struct vkms_device *vkmsdev);
+struct vkms_connector *vkms_connector_init(struct vkms_device *vkmsdev,
+					   struct vkms_config_connector *connector_cfg);
 
 /**
  * vkms_trigger_connector_hotplug() - Update the device's connectors status
diff --git a/drivers/gpu/drm/vkms/vkms_output.c b/drivers/gpu/drm/vkms/vkms_output.c
index 86ce07a617f5..1288c8551bc8 100644
--- a/drivers/gpu/drm/vkms/vkms_output.c
+++ b/drivers/gpu/drm/vkms/vkms_output.c
@@ -97,7 +97,7 @@ int vkms_output_init(struct vkms_device *vkmsdev)
 		struct vkms_config_encoder *possible_encoder;
 		unsigned long idx = 0;
 
-		connector_cfg->connector = vkms_connector_init(vkmsdev);
+		connector_cfg->connector = vkms_connector_init(vkmsdev, connector_cfg);
 		if (IS_ERR(connector_cfg->connector)) {
 			DRM_ERROR("Failed to init connector\n");
 			return PTR_ERR(connector_cfg->connector);

-- 
2.51.2

[PATCH v3 23/33] drm/vkms: Introduce configfs for connector type

[Louis Chauvet]

Add a new attribute to connector to change its type. This is mostly
cosmetic and don't have direct effect in VKMS behavior.

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 Documentation/ABI/testing/configfs-vkms |  7 ++++
 Documentation/gpu/vkms.rst              |  3 +-
 drivers/gpu/drm/vkms/vkms_configfs.c    | 65 +++++++++++++++++++++++++++++++++
 3 files changed, 74 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
index 34cb6aeec411..5452140cc508 100644
--- a/Documentation/ABI/testing/configfs-vkms
+++ b/Documentation/ABI/testing/configfs-vkms
@@ -33,6 +33,13 @@ Description:
         Connection status of the connector. Possible values:
         1 - connected, 2 - disconnected, 3 - unknown.
 
+What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/type
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        Type of the connector. Possible values match those
+        exposed by the "type" field in drm_connector.
+
 What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/possible_encoders
 Date:		Nov 2025
 Contact:	dri-devel@lists.freedesktop.org
diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index 791c4f33a90a..41c6f4733663 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -138,10 +138,11 @@ Last but not least, create one or more connectors::
 
   sudo mkdir /config/vkms/my-vkms/connectors/connector0
 
-Connectors have 1 configurable attribute:
+Connectors have 2 configurable attribute:
 
 - status: Connection status: 1 connected, 2 disconnected, 3 unknown (same values
   as those exposed by the "status" property of a connector)
+- type: Type of connector. Same values as exposed by the "type" field in drm_connector.
 
 To finish the configuration, link the different pipeline items::
 
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index e7f3ab54b5a1..d6a85d6c466f 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -1170,10 +1170,75 @@ static ssize_t connector_status_store(struct config_item *item,
 	return (ssize_t)count;
 }
 
+static ssize_t connector_type_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_connector *connector;
+	int type;
+
+	connector = connector_item_to_vkms_configfs_connector(item);
+
+	scoped_guard(mutex, &connector->dev->lock) {
+		type = vkms_config_connector_get_type(connector->config);
+	}
+
+	return sprintf(page, "%u", type);
+}
+
+static ssize_t connector_type_store(struct config_item *item,
+				    const char *page, size_t count)
+{
+	struct vkms_configfs_connector *connector;
+	int val, ret;
+
+	connector = connector_item_to_vkms_configfs_connector(item);
+
+	ret = kstrtouint(page, 10, &val);
+
+	if (ret)
+		return ret;
+
+	switch (val) {
+	case DRM_MODE_CONNECTOR_Unknown:
+	case DRM_MODE_CONNECTOR_VGA:
+	case DRM_MODE_CONNECTOR_DVII:
+	case DRM_MODE_CONNECTOR_DVID:
+	case DRM_MODE_CONNECTOR_DVIA:
+	case DRM_MODE_CONNECTOR_Composite:
+	case DRM_MODE_CONNECTOR_SVIDEO:
+	case DRM_MODE_CONNECTOR_LVDS:
+	case DRM_MODE_CONNECTOR_Component:
+	case DRM_MODE_CONNECTOR_9PinDIN:
+	case DRM_MODE_CONNECTOR_DisplayPort:
+	case DRM_MODE_CONNECTOR_HDMIA:
+	case DRM_MODE_CONNECTOR_HDMIB:
+	case DRM_MODE_CONNECTOR_TV:
+	case DRM_MODE_CONNECTOR_eDP:
+	case DRM_MODE_CONNECTOR_VIRTUAL:
+	case DRM_MODE_CONNECTOR_DSI:
+	case DRM_MODE_CONNECTOR_DPI:
+	case DRM_MODE_CONNECTOR_SPI:
+	case DRM_MODE_CONNECTOR_USB:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	scoped_guard(mutex, &connector->dev->lock) {
+		if (connector->dev->enabled)
+			return -EBUSY;
+
+		vkms_config_connector_set_type(connector->config, val);
+	}
+
+	return count;
+}
+
 CONFIGFS_ATTR(connector_, status);
+CONFIGFS_ATTR(connector_, type);
 
 static struct configfs_attribute *connector_item_attrs[] = {
 	&connector_attr_status,
+	&connector_attr_type,
 	NULL,
 };
 

-- 
2.51.2

[PATCH v3 24/33] drm/connector: Export drm_get_colorspace_name

[Louis Chauvet]

Export drm_get_colorspace_name so it could be used by VKMS

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/drm_connector.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 4d6dc9ebfdb5..77c2fcd4f222 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -1362,6 +1362,7 @@ const char *drm_get_colorspace_name(enum drm_colorspace colorspace)
 	else
 		return "(null)";
 }
+EXPORT_SYMBOL(drm_get_colorspace_name);
 
 static const u32 hdmi_colorspaces =
 	BIT(DRM_MODE_COLORIMETRY_SMPTE_170M_YCC) |

-- 
2.51.2

[PATCH v3 25/33] drm/vkms: Introduce config for connector supported colorspace

[Louis Chauvet]

To emulate some HDR features of displays, it is required to expose some
properties on HDMI, eDP and DP connectors.

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/tests/vkms_config_test.c |  3 +++
 drivers/gpu/drm/vkms/vkms_config.c            |  5 +++++
 drivers/gpu/drm/vkms/vkms_config.h            | 30 +++++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_connector.c         | 15 ++++++++++++++
 4 files changed, 53 insertions(+)

diff --git a/drivers/gpu/drm/vkms/tests/vkms_config_test.c b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
index 1900cc79db2b..a31fd230c1d4 100644
--- a/drivers/gpu/drm/vkms/tests/vkms_config_test.c
+++ b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
@@ -215,6 +215,9 @@ static void vkms_config_test_default_config(struct kunit *test)
 	vkms_config_for_each_connector(config, connector_cfg) {
 		KUNIT_EXPECT_EQ(test, vkms_config_connector_get_type(connector_cfg),
 				DRM_MODE_CONNECTOR_VIRTUAL);
+		KUNIT_EXPECT_EQ(test,
+				vkms_config_connector_get_supported_colorspaces(connector_cfg),
+				0);
 	}
 
 	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
index 59ce55efb167..de661c85c11f 100644
--- a/drivers/gpu/drm/vkms/vkms_config.c
+++ b/drivers/gpu/drm/vkms/vkms_config.c
@@ -591,6 +591,10 @@ static int vkms_config_show(struct seq_file *m, void *data)
 			   drm_get_connector_status_name(vkms_config_connector_get_status(connector_cfg)));
 		seq_printf(m, "\ttype=%s\n",
 			   drm_get_connector_type_name(vkms_config_connector_get_type(connector_cfg)));
+		seq_puts(m, "\tsupported colorspaces=");
+		show_bitfield(m, vkms_config_connector_get_supported_colorspaces(connector_cfg),
+			      drm_get_colorspace_name);
+		seq_puts(m, "\n");
 	}
 
 	return 0;
@@ -908,6 +912,7 @@ struct vkms_config_connector *vkms_config_create_connector(struct vkms_config *c
 	connector_cfg->config = config;
 	connector_cfg->status = connector_status_connected;
 	vkms_config_connector_set_type(connector_cfg, DRM_MODE_CONNECTOR_VIRTUAL);
+	vkms_config_connector_set_supported_colorspaces(connector_cfg, 0);
 	xa_init_flags(&connector_cfg->possible_encoders, XA_FLAGS_ALLOC);
 
 	list_add_tail(&connector_cfg->link, &config->connectors);
diff --git a/drivers/gpu/drm/vkms/vkms_config.h b/drivers/gpu/drm/vkms/vkms_config.h
index 4a4058b407e7..c9d777589cb6 100644
--- a/drivers/gpu/drm/vkms/vkms_config.h
+++ b/drivers/gpu/drm/vkms/vkms_config.h
@@ -132,6 +132,10 @@ struct vkms_config_encoder {
  * @type: Store the type of connector using DRM_MODE_CONNECTOR_* values
  * @config: The vkms_config this connector belongs to
  * @status: Status (connected, disconnected...) of the connector
+ * @supported_colorspaces: Bitmask of all the supported colorspaces. Values
+ *                         are the sames as ones accepted by
+ *                         drm_mode_create_hdmi_colorspace_property() and
+ *                         drm_mode_create_dp_colorspace_property()
  * @possible_encoders: Array of encoders that can be used with this connector
  * @connector: Internal usage. This pointer should never be considered as valid.
  *             It can be used to store a temporary reference to a VKMS connector
@@ -144,6 +148,7 @@ struct vkms_config_connector {
 
 	int type;
 	enum drm_connector_status status;
+	u32 supported_colorspaces;
 	struct xarray possible_encoders;
 
 	/* Internal usage */
@@ -243,6 +248,31 @@ struct vkms_config *vkms_config_default_create(bool enable_cursor,
  */
 void vkms_config_destroy(struct vkms_config *config);
 
+/**
+ * vkms_config_connector_set_supported_colorspaces() - Set the supported colorspaces for a connector
+ * @connector_cfg: Connector configuration to modify
+ * @supported_colorspaces: Bitmask of supported colorspaces (DRM_MODE_COLORIMETRY_*)
+ */
+static inline void
+vkms_config_connector_set_supported_colorspaces(struct vkms_config_connector *connector_cfg,
+						u32 supported_colorspaces)
+{
+	connector_cfg->supported_colorspaces = supported_colorspaces;
+}
+
+/**
+ * vkms_config_connector_get_supported_colorspaces() - Get the supported colorspaces for a connector
+ * @connector_cfg: Connector configuration to query
+ *
+ * Returns:
+ * Bitmask of supported colorspaces (DRM_MODE_COLORIMETRY_*)
+ */
+static inline u32
+vkms_config_connector_get_supported_colorspaces(const struct vkms_config_connector *connector_cfg)
+{
+	return connector_cfg->supported_colorspaces;
+}
+
 /**
  * vkms_config_get_device_name() - Return the name of the device
  * @config: Configuration to get the device name from
diff --git a/drivers/gpu/drm/vkms/vkms_connector.c b/drivers/gpu/drm/vkms/vkms_connector.c
index 5a87dc2d4c63..cc59d13c2d22 100644
--- a/drivers/gpu/drm/vkms/vkms_connector.c
+++ b/drivers/gpu/drm/vkms/vkms_connector.c
@@ -84,6 +84,21 @@ struct vkms_connector *vkms_connector_init(struct vkms_device *vkmsdev,
 	if (ret)
 		return ERR_PTR(ret);
 
+	if (vkms_config_connector_get_supported_colorspaces(connector_cfg)) {
+		if (connector_cfg->type == DRM_MODE_CONNECTOR_HDMIA) {
+			drm_mode_create_hdmi_colorspace_property(&connector->base,
+								 vkms_config_connector_get_supported_colorspaces(connector_cfg));
+			drm_connector_attach_hdr_output_metadata_property(&connector->base);
+			drm_connector_attach_colorspace_property(&connector->base);
+		} else if (connector_cfg->type == DRM_MODE_CONNECTOR_DisplayPort ||
+			   connector_cfg->type == DRM_MODE_CONNECTOR_eDP) {
+			drm_mode_create_dp_colorspace_property(&connector->base,
+							       vkms_config_connector_get_supported_colorspaces(connector_cfg));
+			drm_connector_attach_hdr_output_metadata_property(&connector->base);
+			drm_connector_attach_colorspace_property(&connector->base);
+		}
+	}
+
 	drm_connector_helper_add(&connector->base, &vkms_conn_helper_funcs);
 
 	return connector;

-- 
2.51.2

[PATCH v3 26/33] drm/vkms: Introduce configfs for connector supported colorspace

[Louis Chauvet]

Add the attribute supported_colorspaces to configure the supported
colorspace of a connector. It will allows emulating some HDR features of
displays. This feature is only supported for HDMI, DP and eDP connectors.

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 Documentation/ABI/testing/configfs-vkms |  8 +++++++
 Documentation/gpu/vkms.rst              |  7 +++++-
 drivers/gpu/drm/vkms/vkms_configfs.c    | 40 +++++++++++++++++++++++++++++++++
 3 files changed, 54 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
index 5452140cc508..f750e616be54 100644
--- a/Documentation/ABI/testing/configfs-vkms
+++ b/Documentation/ABI/testing/configfs-vkms
@@ -40,6 +40,14 @@ Description:
         Type of the connector. Possible values match those
         exposed by the "type" field in drm_connector.
 
+What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/supported_colorspaces
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        Supported colorspaces for HDMI, DP, and eDP connectors.
+        Value is a bitfield, where 0x1 = NO_DATA, 0x2 = SMPTE_170M_YCC,
+        etc. See enum drm_colorspace for full list.
+
 What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/possible_encoders
 Date:		Nov 2025
 Contact:	dri-devel@lists.freedesktop.org
diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index 41c6f4733663..1c4a8023374c 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -138,11 +138,16 @@ Last but not least, create one or more connectors::
 
   sudo mkdir /config/vkms/my-vkms/connectors/connector0
 
-Connectors have 2 configurable attribute:
+Connectors have 3 configurable attribute:
 
 - status: Connection status: 1 connected, 2 disconnected, 3 unknown (same values
   as those exposed by the "status" property of a connector)
 - type: Type of connector. Same values as exposed by the "type" field in drm_connector.
+- supported_colorspaces: Supported colorspaces values for HDMI, DP and eDP connectors.
+  If supported_colorspaces is not 0, the HDR_OUTPUT_METADATA will also be created.
+  Value is a bitfield, 0x1 = NO_DATA, 0x2 = SMPTE_170M_YCC... see enum drm_colorspace
+  for full list.
+
 
 To finish the configuration, link the different pipeline items::
 
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index d6a85d6c466f..90bf6e6995ae 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -1233,12 +1233,52 @@ static ssize_t connector_type_store(struct config_item *item,
 	return count;
 }
 
+static ssize_t connector_supported_colorspaces_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_connector *connector;
+	int colorspaces;
+
+	connector = connector_item_to_vkms_configfs_connector(item);
+
+	scoped_guard(mutex, &connector->dev->lock)
+	colorspaces = vkms_config_connector_get_supported_colorspaces(connector->config);
+
+	return sprintf(page, "%u", colorspaces);
+}
+
+static ssize_t connector_supported_colorspaces_store(struct config_item *item,
+						     const char *page, size_t count)
+{
+	struct vkms_configfs_connector *connector;
+	int val, ret;
+
+	connector = connector_item_to_vkms_configfs_connector(item);
+
+	ret = kstrtouint(page, 10, &val);
+	if (ret)
+		return ret;
+
+	if ((val & -BIT(DRM_MODE_COLORIMETRY_COUNT)) != 0)
+		return -EINVAL;
+
+	scoped_guard(mutex, &connector->dev->lock) {
+		if (connector->dev->enabled)
+			return -EBUSY;
+
+		vkms_config_connector_set_supported_colorspaces(connector->config, val);
+	}
+
+	return count;
+}
+
 CONFIGFS_ATTR(connector_, status);
 CONFIGFS_ATTR(connector_, type);
+CONFIGFS_ATTR(connector_, supported_colorspaces);
 
 static struct configfs_attribute *connector_item_attrs[] = {
 	&connector_attr_status,
 	&connector_attr_type,
+	&connector_attr_supported_colorspaces,
 	NULL,
 };
 

-- 
2.51.2

[PATCH v3 27/33] drm/vkms: Introduce config for connector EDID

[Louis Chauvet]

Allows configuration of EDID for each connector.

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/tests/vkms_config_test.c |  2 +
 drivers/gpu/drm/vkms/vkms_config.c            |  6 +++
 drivers/gpu/drm/vkms/vkms_config.h            | 75 +++++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_connector.c         | 50 ++++++++++++++++--
 4 files changed, 129 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/vkms/tests/vkms_config_test.c b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
index a31fd230c1d4..2b49745ee026 100644
--- a/drivers/gpu/drm/vkms/tests/vkms_config_test.c
+++ b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
@@ -218,6 +218,8 @@ static void vkms_config_test_default_config(struct kunit *test)
 		KUNIT_EXPECT_EQ(test,
 				vkms_config_connector_get_supported_colorspaces(connector_cfg),
 				0);
+		KUNIT_EXPECT_EQ(test, vkms_config_connector_get_edid_enabled(connector_cfg),
+				false);
 	}
 
 	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
index de661c85c11f..adb1a384c122 100644
--- a/drivers/gpu/drm/vkms/vkms_config.c
+++ b/drivers/gpu/drm/vkms/vkms_config.c
@@ -525,6 +525,7 @@ static int vkms_config_show(struct seq_file *m, void *data)
 	struct drm_device *dev = entry->dev;
 	struct vkms_device *vkmsdev = drm_device_to_vkms_device(dev);
 	const char *dev_name;
+	int edid_len;
 	struct vkms_config_plane *plane_cfg;
 	struct vkms_config_crtc *crtc_cfg;
 	struct vkms_config_encoder *encoder_cfg;
@@ -595,6 +596,11 @@ static int vkms_config_show(struct seq_file *m, void *data)
 		show_bitfield(m, vkms_config_connector_get_supported_colorspaces(connector_cfg),
 			      drm_get_colorspace_name);
 		seq_puts(m, "\n");
+		vkms_config_connector_get_edid(connector_cfg, &edid_len);
+		seq_printf(m, "\tEDID=%s (len=%d)\n",
+			   str_enabled_disabled(vkms_config_connector_get_edid_enabled(connector_cfg)),
+			   edid_len
+		);
 	}
 
 	return 0;
diff --git a/drivers/gpu/drm/vkms/vkms_config.h b/drivers/gpu/drm/vkms/vkms_config.h
index c9d777589cb6..7cca1cc130b0 100644
--- a/drivers/gpu/drm/vkms/vkms_config.h
+++ b/drivers/gpu/drm/vkms/vkms_config.h
@@ -136,6 +136,9 @@ struct vkms_config_encoder {
  *                         are the sames as ones accepted by
  *                         drm_mode_create_hdmi_colorspace_property() and
  *                         drm_mode_create_dp_colorspace_property()
+ * @edid_enabled: If true, create the EDID property
+ * @edid: Stores the current EDID. The value will be ignored if @edid_enabled is false
+ * @edid_len: Current EDID length. The value will be ignored if @edid_enabled is false
  * @possible_encoders: Array of encoders that can be used with this connector
  * @connector: Internal usage. This pointer should never be considered as valid.
  *             It can be used to store a temporary reference to a VKMS connector
@@ -149,6 +152,9 @@ struct vkms_config_connector {
 	int type;
 	enum drm_connector_status status;
 	u32 supported_colorspaces;
+	bool edid_enabled;
+	u8 *edid;
+	unsigned int edid_len;
 	struct xarray possible_encoders;
 
 	/* Internal usage */
@@ -273,6 +279,75 @@ vkms_config_connector_get_supported_colorspaces(const struct vkms_config_connect
 	return connector_cfg->supported_colorspaces;
 }
 
+/**
+ * vkms_config_connector_get_edid_enabled() - Check if EDID is enabled for a connector
+ * @connector_cfg: Connector configuration to check
+ *
+ * Returns:
+ * True if EDID is enabled for this connector, false otherwise.
+ */
+static inline bool
+vkms_config_connector_get_edid_enabled(const struct vkms_config_connector *connector_cfg)
+{
+	return connector_cfg->edid_enabled;
+}
+
+/**
+ * vkms_config_connector_set_edid_enabled() - Enable or disable EDID for a connector
+ * @connector_cfg: Connector configuration to modify
+ * @enabled: Whether to enable EDID for this connector
+ */
+static inline void
+vkms_config_connector_set_edid_enabled(struct vkms_config_connector *connector_cfg,
+				       bool enabled)
+{
+	connector_cfg->edid_enabled = enabled;
+}
+
+/**
+ * vkms_config_connector_get_edid() - Get the EDID data for a connector
+ * @connector_cfg: Connector configuration to get the EDID from
+ * @len: Pointer to store the length of the EDID data
+ *
+ * Returns:
+ * Pointer to the EDID data buffer, or NULL if no EDID is set.
+ * The length of the EDID data is stored in @len.
+ */
+static inline const u8 *
+vkms_config_connector_get_edid(const struct vkms_config_connector *connector_cfg, int *len)
+{
+	*len = connector_cfg->edid_len;
+	return connector_cfg->edid;
+}
+
+/**
+ * vkms_config_connector_set_edid() - Set the EDID data for a connector
+ * @connector_cfg: Connector configuration to modify
+ * @edid: Pointer to the EDID data buffer
+ * @len: Length of the EDID data
+ *
+ * If @len is 0, the EDID data will be cleared and @edid ignored. If
+ * memory allocation fails, the existing EDID data will be preserved.
+ */
+static inline void
+vkms_config_connector_set_edid(struct vkms_config_connector *connector_cfg,
+			       const u8 *edid, unsigned int len)
+{
+	if (len) {
+		void *edid_tmp = krealloc(connector_cfg->edid, len, GFP_KERNEL);
+
+		if (edid_tmp) {
+			connector_cfg->edid = edid_tmp;
+			memcpy(connector_cfg->edid, edid, len);
+			connector_cfg->edid_len = len;
+		}
+	} else {
+		kfree(connector_cfg->edid);
+		connector_cfg->edid = NULL;
+		connector_cfg->edid_len = len;
+	}
+}
+
 /**
  * vkms_config_get_device_name() - Return the name of the device
  * @config: Configuration to get the device name from
diff --git a/drivers/gpu/drm/vkms/vkms_connector.c b/drivers/gpu/drm/vkms/vkms_connector.c
index cc59d13c2d22..c85d19013720 100644
--- a/drivers/gpu/drm/vkms/vkms_connector.c
+++ b/drivers/gpu/drm/vkms/vkms_connector.c
@@ -42,13 +42,55 @@ static const struct drm_connector_funcs vkms_connector_funcs = {
 	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
 };
 
+static int vkms_connector_read_block(void *context, u8 *buf, unsigned int block, size_t len)
+{
+	struct vkms_config_connector *config = context;
+	unsigned int edid_len;
+	const u8 *edid = vkms_config_connector_get_edid(config, &edid_len);
+
+	if (block * len + len > edid_len)
+		return 1;
+	memcpy(buf, &edid[block * len], len);
+	return 0;
+}
+
 static int vkms_conn_get_modes(struct drm_connector *connector)
 {
-	int count;
+	struct vkms_connector *vkms_connector = drm_connector_to_vkms_connector(connector);
+	const struct drm_edid *drm_edid = NULL;
+	int count = 0;
+	struct vkms_config_connector *context = NULL;
+	struct drm_device *dev = connector->dev;
+	struct vkms_device *vkmsdev = drm_device_to_vkms_device(dev);
+	struct vkms_config_connector *connector_cfg;
 
-	/* Use the default modes list from DRM */
-	count = drm_add_modes_noedid(connector, XRES_MAX, YRES_MAX);
-	drm_set_preferred_mode(connector, XRES_DEF, YRES_DEF);
+	vkms_config_for_each_connector(vkmsdev->config, connector_cfg) {
+		if (connector_cfg->connector == vkms_connector) {
+			context = connector_cfg;
+			break;
+		}
+	}
+	if (context) {
+		if (vkms_config_connector_get_edid_enabled(context)) {
+			drm_edid = drm_edid_read_custom(connector,
+							vkms_connector_read_block, context);
+
+			/*
+			 * Unconditionally update the connector. If the EDID was read
+			 * successfully, fill in the connector information derived from the
+			 * EDID. Otherwise, if the EDID is NULL, clear the connector
+			 * information.
+			 */
+			drm_edid_connector_update(connector, drm_edid);
+
+			count = drm_edid_connector_add_modes(connector);
+
+			drm_edid_free(drm_edid);
+		} else {
+			count = drm_add_modes_noedid(connector, XRES_MAX, YRES_MAX);
+			drm_set_preferred_mode(connector, XRES_DEF, YRES_DEF);
+		}
+	}
 
 	return count;
 }

-- 
2.51.2

[PATCH v3 28/33] drm/vkms: Introduce configfs for connector EDID

[Louis Chauvet]

Introduce new attributes to configure EDID of a connector:
- edid_enable - chose if the connector will have an EDID or not
- edid - raw edid content

Due to limitation of ConfigFS, the max len of EDID is PAGE_SIZE (4kB on
x86), it should be sufficient for many tests. One possible evolution is
using a ConfigFS blob to allow bigger EDID.

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 Documentation/ABI/testing/configfs-vkms | 14 ++++++
 Documentation/gpu/vkms.rst              |  5 ++-
 drivers/gpu/drm/vkms/vkms_configfs.c    | 80 +++++++++++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_connector.c   |  3 ++
 4 files changed, 101 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
index f750e616be54..4061ada5d88b 100644
--- a/Documentation/ABI/testing/configfs-vkms
+++ b/Documentation/ABI/testing/configfs-vkms
@@ -48,6 +48,20 @@ Description:
         Value is a bitfield, where 0x1 = NO_DATA, 0x2 = SMPTE_170M_YCC,
         etc. See enum drm_colorspace for full list.
 
+What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/edid_enabled
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        Enable or disable EDID for this connector. Value:
+        1 - enabled, 0 - disabled.
+
+What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/edid
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        Content of the EDID for this connector. Ignored if
+        edid_enabled is not set.
+
 What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/possible_encoders
 Date:		Nov 2025
 Contact:	dri-devel@lists.freedesktop.org
diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index 1c4a8023374c..60367fd1bd65 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -138,7 +138,7 @@ Last but not least, create one or more connectors::
 
   sudo mkdir /config/vkms/my-vkms/connectors/connector0
 
-Connectors have 3 configurable attribute:
+Connectors have 5 configurable attribute:
 
 - status: Connection status: 1 connected, 2 disconnected, 3 unknown (same values
   as those exposed by the "status" property of a connector)
@@ -147,6 +147,9 @@ Connectors have 3 configurable attribute:
   If supported_colorspaces is not 0, the HDR_OUTPUT_METADATA will also be created.
   Value is a bitfield, 0x1 = NO_DATA, 0x2 = SMPTE_170M_YCC... see enum drm_colorspace
   for full list.
+- edid_enabled: Enable or not EDID for this connector. Some connectors may not have an
+  EDID but just a list of modes, this attribute allows to disable EDID property.
+- edid: Content of the EDID. Ignored if edid_enabled is not set
 
 
 To finish the configuration, link the different pipeline items::
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index 90bf6e6995ae..20f5150e8b24 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -1271,14 +1271,94 @@ static ssize_t connector_supported_colorspaces_store(struct config_item *item,
 	return count;
 }
 
+static ssize_t connector_edid_enabled_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_connector *connector;
+	bool enabled;
+
+	connector = connector_item_to_vkms_configfs_connector(item);
+
+	scoped_guard(mutex, &connector->dev->lock)
+		enabled = vkms_config_connector_get_edid_enabled(connector->config);
+
+	return sprintf(page, "%d\n", enabled);
+}
+
+static ssize_t connector_edid_enabled_store(struct config_item *item,
+					    const char *page, size_t count)
+{
+	struct vkms_configfs_connector *connector;
+	struct vkms_config_connector *connector_cfg;
+	bool enabled;
+
+	connector = connector_item_to_vkms_configfs_connector(item);
+	connector_cfg = connector->config;
+
+	if (kstrtobool(page, &enabled))
+		return -EINVAL;
+
+	scoped_guard(mutex, &connector->dev->lock)
+	{
+		vkms_config_connector_set_edid_enabled(connector_cfg, enabled);
+
+		if (connector->dev->enabled &&
+		    vkms_config_connector_get_status(connector_cfg) !=
+		    connector_status_disconnected)
+			vkms_trigger_connector_hotplug(connector->dev->config->dev);
+	}
+	return count;
+}
+
+static ssize_t connector_edid_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_connector *connector;
+
+	connector = connector_item_to_vkms_configfs_connector(item);
+
+	scoped_guard(mutex, &connector->dev->lock)
+	{
+		unsigned int len = 0;
+		const u8 *edid = vkms_config_connector_get_edid(connector->config, &len);
+
+		memcpy(page, edid, min(len, PAGE_SIZE));
+		return min(len, PAGE_SIZE);
+	}
+
+	return -EINVAL;
+}
+
+static ssize_t connector_edid_store(struct config_item *item,
+				    const char *page, size_t count)
+{
+	struct vkms_configfs_connector *connector;
+
+	connector = connector_item_to_vkms_configfs_connector(item);
+
+	scoped_guard(mutex, &connector->dev->lock)
+	{
+		vkms_config_connector_set_edid(connector->config, page, count);
+
+		if (connector->dev->enabled &&
+		    vkms_config_connector_get_status(connector->config) !=
+		    connector_status_disconnected)
+			vkms_trigger_connector_hotplug(connector->dev->config->dev);
+	}
+
+	return count;
+}
+
 CONFIGFS_ATTR(connector_, status);
 CONFIGFS_ATTR(connector_, type);
 CONFIGFS_ATTR(connector_, supported_colorspaces);
+CONFIGFS_ATTR(connector_, edid_enabled);
+CONFIGFS_ATTR(connector_, edid);
 
 static struct configfs_attribute *connector_item_attrs[] = {
 	&connector_attr_status,
 	&connector_attr_type,
 	&connector_attr_supported_colorspaces,
+	&connector_attr_edid_enabled,
+	&connector_attr_edid,
 	NULL,
 };
 
diff --git a/drivers/gpu/drm/vkms/vkms_connector.c b/drivers/gpu/drm/vkms/vkms_connector.c
index c85d19013720..311858727175 100644
--- a/drivers/gpu/drm/vkms/vkms_connector.c
+++ b/drivers/gpu/drm/vkms/vkms_connector.c
@@ -143,6 +143,9 @@ struct vkms_connector *vkms_connector_init(struct vkms_device *vkmsdev,
 
 	drm_connector_helper_add(&connector->base, &vkms_conn_helper_funcs);
 
+	if (vkms_config_connector_get_edid_enabled(connector_cfg))
+		drm_connector_attach_edid_property(&connector->base);
+
 	return connector;
 }
 

-- 
2.51.2

[PATCH v3 29/33] drm/vkms: Store the enabled/disabled status for connector

[Louis Chauvet]

In order to prepare for dynamic connector configuration, we need to store
if a connector is dynamic and if it is enabled.

The two new vkms_config_connector fields will helps for that.

Co-developed-by: José Expósito <jose.exposito89@gmail.com>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/tests/vkms_config_test.c |  4 ++
 drivers/gpu/drm/vkms/vkms_config.c            |  6 +++
 drivers/gpu/drm/vkms/vkms_config.h            | 66 +++++++++++++++++++++++++++
 3 files changed, 76 insertions(+)

diff --git a/drivers/gpu/drm/vkms/tests/vkms_config_test.c b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
index 2b49745ee026..fda23f05a0a5 100644
--- a/drivers/gpu/drm/vkms/tests/vkms_config_test.c
+++ b/drivers/gpu/drm/vkms/tests/vkms_config_test.c
@@ -220,6 +220,10 @@ static void vkms_config_test_default_config(struct kunit *test)
 				0);
 		KUNIT_EXPECT_EQ(test, vkms_config_connector_get_edid_enabled(connector_cfg),
 				false);
+		KUNIT_EXPECT_EQ(test, vkms_config_connector_is_enabled(connector_cfg),
+				true);
+		KUNIT_EXPECT_EQ(test, vkms_config_connector_is_dynamic(connector_cfg),
+				false);
 	}
 
 	KUNIT_EXPECT_TRUE(test, vkms_config_is_valid(config));
diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
index adb1a384c122..8abf9efc12e6 100644
--- a/drivers/gpu/drm/vkms/vkms_config.c
+++ b/drivers/gpu/drm/vkms/vkms_config.c
@@ -588,6 +588,8 @@ static int vkms_config_show(struct seq_file *m, void *data)
 
 	vkms_config_for_each_connector(vkmsdev->config, connector_cfg) {
 		seq_puts(m, "connector:\n");
+		seq_printf(m, "\t%s\n",
+			   str_enabled_disabled(vkms_config_connector_is_enabled(connector_cfg)));
 		seq_printf(m, "\tstatus=%s\n",
 			   drm_get_connector_status_name(vkms_config_connector_get_status(connector_cfg)));
 		seq_printf(m, "\ttype=%s\n",
@@ -601,6 +603,8 @@ static int vkms_config_show(struct seq_file *m, void *data)
 			   str_enabled_disabled(vkms_config_connector_get_edid_enabled(connector_cfg)),
 			   edid_len
 		);
+		seq_printf(m, "\tdynamic=%s\n",
+			   str_true_false(vkms_config_connector_is_dynamic(connector_cfg)));
 	}
 
 	return 0;
@@ -919,6 +923,8 @@ struct vkms_config_connector *vkms_config_create_connector(struct vkms_config *c
 	connector_cfg->status = connector_status_connected;
 	vkms_config_connector_set_type(connector_cfg, DRM_MODE_CONNECTOR_VIRTUAL);
 	vkms_config_connector_set_supported_colorspaces(connector_cfg, 0);
+	vkms_config_connector_set_dynamic(connector_cfg, false);
+	vkms_config_connector_set_enabled(connector_cfg, true);
 	xa_init_flags(&connector_cfg->possible_encoders, XA_FLAGS_ALLOC);
 
 	list_add_tail(&connector_cfg->link, &config->connectors);
diff --git a/drivers/gpu/drm/vkms/vkms_config.h b/drivers/gpu/drm/vkms/vkms_config.h
index 7cca1cc130b0..281434628e0e 100644
--- a/drivers/gpu/drm/vkms/vkms_config.h
+++ b/drivers/gpu/drm/vkms/vkms_config.h
@@ -131,6 +131,8 @@ struct vkms_config_encoder {
  * @link: Link to the others connector in vkms_config
  * @type: Store the type of connector using DRM_MODE_CONNECTOR_* values
  * @config: The vkms_config this connector belongs to
+ * @dynamic: Store if a connector should be created with drm_connector_dynamic_init
+ * @enabled: If @dynamic, this means that the connector is currently registered in drm
  * @status: Status (connected, disconnected...) of the connector
  * @supported_colorspaces: Bitmask of all the supported colorspaces. Values
  *                         are the sames as ones accepted by
@@ -150,6 +152,8 @@ struct vkms_config_connector {
 	struct vkms_config *config;
 
 	int type;
+	bool enabled;
+	bool dynamic;
 	enum drm_connector_status status;
 	u32 supported_colorspaces;
 	bool edid_enabled;
@@ -193,6 +197,24 @@ struct vkms_config_connector {
 #define vkms_config_for_each_connector(config, connector_cfg) \
 	list_for_each_entry((connector_cfg), &(config)->connectors, link)
 
+/**
+ * vkms_config_for_each_connector_static - Iterate over the static vkms_config connectors
+ * @config: &struct vkms_config pointer
+ * @connector_cfg: &struct vkms_config_connector pointer used as cursor
+ */
+#define vkms_config_for_each_connector_static(config, connector_cfg) \
+	vkms_config_for_each_connector((config), (connector_cfg)) \
+		if (!(connector_cfg)->dynamic)
+
+/**
+ * vkms_config_for_each_connector_dynamic - Iterate over the dynamic vkms_config connectors
+ * @config: &struct vkms_config pointer
+ * @connector_cfg: &struct vkms_config_connector pointer used as cursor
+ */
+#define vkms_config_for_each_connector_dynamic(config, connector_cfg) \
+	vkms_config_for_each_connector((config), (connector_cfg)) \
+		if ((connector_cfg)->dynamic)
+
 /**
  * vkms_config_plane_for_each_possible_crtc - Iterate over the vkms_config_plane
  * possible CRTCs
@@ -471,6 +493,50 @@ vkms_config_connector_set_type(struct vkms_config_connector *connector_cfg,
 	connector_cfg->type = type;
 }
 
+/**
+ * vkms_config_connector_set_enabled() - If the connector is part of the device
+ * @crtc_cfg: Target connector
+ * @enabled: Add or remove the connector
+ */
+static inline void
+vkms_config_connector_set_enabled(struct vkms_config_connector *connector_cfg,
+				  bool enabled)
+{
+	connector_cfg->enabled = enabled;
+}
+
+/**
+ * vkms_config_connector_is_enabled() - If the connector is part of the device
+ * @connector_cfg: The connector
+ */
+static inline bool
+vkms_config_connector_is_enabled(const struct vkms_config_connector *connector_cfg)
+{
+	return connector_cfg->enabled;
+}
+
+/**
+ * vkms_config_connector_set_dynamic() - If the connector is dynamic
+ * @crtc_cfg: Target connector
+ * @enabled: Enable or disable the dynamic status
+ */
+static inline void
+vkms_config_connector_set_dynamic(struct vkms_config_connector *connector_cfg,
+				  bool dynamic)
+{
+	connector_cfg->dynamic = dynamic;
+}
+
+/**
+ * vkms_config_connector_is_enabled() - If the connector is dynamic
+ * @connector_cfg: The connector
+ */
+static inline bool
+vkms_config_connector_is_dynamic(struct vkms_config_connector *connector_cfg)
+{
+	return connector_cfg->dynamic;
+}
+
 /*
  * vkms_config_plane_get_default_rotation() - Get the default rotation for a plane
  * @plane_cfg: Plane to get the default rotation from

-- 
2.51.2

[PATCH v3 30/33] drm/vkms: Rename vkms_connector_init to vkms_connector_init_static

[Louis Chauvet]

With the introduction of dynamic connectors we will have two way of
initializing a VKMS connector. Rename the current function to clarify
the case.

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/vkms_connector.c | 4 ++--
 drivers/gpu/drm/vkms/vkms_connector.h | 6 +++---
 drivers/gpu/drm/vkms/vkms_output.c    | 4 ++--
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_connector.c b/drivers/gpu/drm/vkms/vkms_connector.c
index 311858727175..211f11c8473d 100644
--- a/drivers/gpu/drm/vkms/vkms_connector.c
+++ b/drivers/gpu/drm/vkms/vkms_connector.c
@@ -110,8 +110,8 @@ static const struct drm_connector_helper_funcs vkms_conn_helper_funcs = {
 	.best_encoder = vkms_conn_best_encoder,
 };
 
-struct vkms_connector *vkms_connector_init(struct vkms_device *vkmsdev,
-					   struct vkms_config_connector *connector_cfg)
+struct vkms_connector *vkms_connector_init_static(struct vkms_device *vkmsdev,
+						  struct vkms_config_connector *connector_cfg)
 {
 	struct drm_device *dev = &vkmsdev->drm;
 	struct vkms_connector *connector;
diff --git a/drivers/gpu/drm/vkms/vkms_connector.h b/drivers/gpu/drm/vkms/vkms_connector.h
index 33253d29b1cc..85f9082c710e 100644
--- a/drivers/gpu/drm/vkms/vkms_connector.h
+++ b/drivers/gpu/drm/vkms/vkms_connector.h
@@ -19,14 +19,14 @@ struct vkms_connector {
 };
 
 /**
- * vkms_connector_init() - Initialize a connector
+ * vkms_connector_init_static() - Initialize a connector
  * @vkmsdev: VKMS device containing the connector
  *
  * Returns:
  * The connector or an error on failure.
  */
-struct vkms_connector *vkms_connector_init(struct vkms_device *vkmsdev,
-					   struct vkms_config_connector *connector_cfg);
+struct vkms_connector *vkms_connector_init_static(struct vkms_device *vkmsdev,
+						  struct vkms_config_connector *connector_cfg);
 
 /**
  * vkms_trigger_connector_hotplug() - Update the device's connectors status
diff --git a/drivers/gpu/drm/vkms/vkms_output.c b/drivers/gpu/drm/vkms/vkms_output.c
index 1288c8551bc8..13c4ca5fd39d 100644
--- a/drivers/gpu/drm/vkms/vkms_output.c
+++ b/drivers/gpu/drm/vkms/vkms_output.c
@@ -93,11 +93,11 @@ int vkms_output_init(struct vkms_device *vkmsdev)
 		}
 	}
 
-	vkms_config_for_each_connector(vkmsdev->config, connector_cfg) {
+	vkms_config_for_each_connector_static(vkmsdev->config, connector_cfg) {
 		struct vkms_config_encoder *possible_encoder;
 		unsigned long idx = 0;
 
-		connector_cfg->connector = vkms_connector_init(vkmsdev, connector_cfg);
+		connector_cfg->connector = vkms_connector_init_static(vkmsdev, connector_cfg);
 		if (IS_ERR(connector_cfg->connector)) {
 			DRM_ERROR("Failed to init connector\n");
 			return PTR_ERR(connector_cfg->connector);

-- 
2.51.2

[PATCH v3 31/33] drm/vkms: Extract common code for connector initialization

[Louis Chauvet]

With the introduction of dynamic connector, some code will be shared
between dynamic and static connectors. Extract this part to avoid code
duplication

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/vkms_connector.c | 44 +++++++++++++++++++++++------------
 1 file changed, 29 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_connector.c b/drivers/gpu/drm/vkms/vkms_connector.c
index 211f11c8473d..3ad614642355 100644
--- a/drivers/gpu/drm/vkms/vkms_connector.c
+++ b/drivers/gpu/drm/vkms/vkms_connector.c
@@ -110,22 +110,17 @@ static const struct drm_connector_helper_funcs vkms_conn_helper_funcs = {
 	.best_encoder = vkms_conn_best_encoder,
 };
 
-struct vkms_connector *vkms_connector_init_static(struct vkms_device *vkmsdev,
-						  struct vkms_config_connector *connector_cfg)
+/**
+ * vkms_connector_init() - Common initialization of vkms connector
+ * @vkmsdev: VKMS device containing the device
+ * @connector: VKMS connector to init. @connector->base must be
+ *             already initialized by DRM core.
+ * @connector_cfg: Connector configuration to apply
+ */
+static void vkms_connector_init(struct vkms_device *vkmsdev,
+				struct vkms_connector *connector,
+				const struct vkms_config_connector *connector_cfg)
 {
-	struct drm_device *dev = &vkmsdev->drm;
-	struct vkms_connector *connector;
-	int ret;
-
-	connector = drmm_kzalloc(dev, sizeof(*connector), GFP_KERNEL);
-	if (!connector)
-		return ERR_PTR(-ENOMEM);
-
-	ret = drmm_connector_init(dev, &connector->base, &vkms_connector_funcs,
-				  vkms_config_connector_get_type(connector_cfg), NULL);
-	if (ret)
-		return ERR_PTR(ret);
-
 	if (vkms_config_connector_get_supported_colorspaces(connector_cfg)) {
 		if (connector_cfg->type == DRM_MODE_CONNECTOR_HDMIA) {
 			drm_mode_create_hdmi_colorspace_property(&connector->base,
@@ -145,6 +140,25 @@ struct vkms_connector *vkms_connector_init_static(struct vkms_device *vkmsdev,
 
 	if (vkms_config_connector_get_edid_enabled(connector_cfg))
 		drm_connector_attach_edid_property(&connector->base);
+}
+
+struct vkms_connector *vkms_connector_init_static(struct vkms_device *vkmsdev,
+						  struct vkms_config_connector *connector_cfg)
+{
+	struct drm_device *dev = &vkmsdev->drm;
+	struct vkms_connector *connector;
+	int ret;
+
+	connector = drmm_kzalloc(dev, sizeof(*connector), GFP_KERNEL);
+	if (!connector)
+		return ERR_PTR(-ENOMEM);
+
+	ret = drmm_connector_init(dev, &connector->base, &vkms_connector_funcs,
+				  vkms_config_connector_get_type(connector_cfg), NULL);
+	if (ret)
+		return ERR_PTR(ret);
+
+	vkms_connector_init(vkmsdev, connector, connector_cfg);
 
 	return connector;
 }

-- 
2.51.2

[PATCH v3 32/33] drm/vkms: Allow to hot-add connectors

[Louis Chauvet]

In order to allow creating dynamic connector, add the required
infrastructure in vkms_connector.

[Louis Chauvet: use drm_atomic_helper_connector_reset instead of
drm_mode_config_reset because connector is not yet registered]

Co-developed-by: José Expósito <jose.exposito89@gmail.com>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 drivers/gpu/drm/vkms/vkms_connector.c | 81 +++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_connector.h | 33 ++++++++++++++
 drivers/gpu/drm/vkms/vkms_output.c    |  9 ++++
 3 files changed, 123 insertions(+)

diff --git a/drivers/gpu/drm/vkms/vkms_connector.c b/drivers/gpu/drm/vkms/vkms_connector.c
index 3ad614642355..616036494937 100644
--- a/drivers/gpu/drm/vkms/vkms_connector.c
+++ b/drivers/gpu/drm/vkms/vkms_connector.c
@@ -163,9 +163,90 @@ struct vkms_connector *vkms_connector_init_static(struct vkms_device *vkmsdev,
 	return connector;
 }
 
+static void vkms_connector_dynamic_destroy(struct drm_connector *connector)
+{
+	struct drm_device *dev = connector->dev;
+	struct vkms_connector *vkms_connector;
+
+	drm_connector_cleanup(connector);
+
+	vkms_connector = drm_connector_to_vkms_connector(connector);
+	drmm_kfree(dev, vkms_connector);
+}
+
+static const struct drm_connector_funcs vkms_dynamic_connector_funcs = {
+	.fill_modes = drm_helper_probe_single_connector_modes,
+	.reset = drm_atomic_helper_connector_reset,
+	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+	.destroy = vkms_connector_dynamic_destroy,
+	.detect = vkms_connector_detect,
+};
+
 void vkms_trigger_connector_hotplug(struct vkms_device *vkmsdev)
 {
 	struct drm_device *dev = &vkmsdev->drm;
 
 	drm_kms_helper_hotplug_event(dev);
 }
+
+struct vkms_connector *vkms_connector_hot_add(struct vkms_device *vkmsdev,
+					      struct vkms_config_connector *connector_cfg)
+{
+	struct vkms_config_encoder *encoder_cfg;
+	struct vkms_connector *connector;
+	int ret;
+	unsigned long idx = 0;
+
+	connector = drmm_kzalloc(&vkmsdev->drm, sizeof(*connector), GFP_KERNEL);
+	if (IS_ERR(connector))
+		return connector;
+	ret = drm_connector_dynamic_init(&vkmsdev->drm,
+					 &connector->base,
+					 &vkms_dynamic_connector_funcs,
+					 connector_cfg->type,
+					 NULL);
+	if (ret)
+		return ERR_PTR(ret);
+	drm_connector_helper_add(&connector->base, &vkms_conn_helper_funcs);
+
+	vkms_config_connector_for_each_possible_encoder(connector_cfg, idx, encoder_cfg) {
+		ret = drm_connector_attach_encoder(&connector->base,
+						   encoder_cfg->encoder);
+		if (ret)
+			return ERR_PTR(ret);
+	}
+
+	drm_atomic_helper_connector_reset(&connector->base);
+
+	vkms_connector_init(vkmsdev, connector, connector_cfg);
+
+	ret = drm_connector_dynamic_register(&connector->base);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return connector;
+}
+
+void vkms_connector_hot_remove(struct vkms_device *vkmsdev,
+			       struct vkms_connector *connector)
+{
+	drm_connector_unregister(&connector->base);
+	drm_mode_config_reset(&vkmsdev->drm);
+	drm_connector_put(&connector->base);
+}
+
+int vkms_connector_hot_attach_encoder(struct vkms_device *vkmsdev,
+				      struct vkms_connector *connector,
+				      struct drm_encoder *encoder)
+{
+	int ret;
+
+	ret = drm_connector_attach_encoder(&connector->base, encoder);
+	if (ret)
+		return ret;
+
+	drm_mode_config_reset(&vkmsdev->drm);
+
+	return ret;
+}
diff --git a/drivers/gpu/drm/vkms/vkms_connector.h b/drivers/gpu/drm/vkms/vkms_connector.h
index 85f9082c710e..a235a518d5a0 100644
--- a/drivers/gpu/drm/vkms/vkms_connector.h
+++ b/drivers/gpu/drm/vkms/vkms_connector.h
@@ -34,4 +34,37 @@ struct vkms_connector *vkms_connector_init_static(struct vkms_device *vkmsdev,
  */
 void vkms_trigger_connector_hotplug(struct vkms_device *vkmsdev);
 
+/**
+ * vkms_connector_hot_add() - Create a connector after the device is created
+ * @vkmsdev: Device to hot-add the connector to
+ * @connector_cfg: Connector's configuration
+ *
+ * Returns:
+ * A pointer to the newly created connector or a PTR_ERR on failure.
+ */
+struct vkms_connector *vkms_connector_hot_add(struct vkms_device *vkmsdev,
+					      struct vkms_config_connector *connector_cfg);
+
+/**
+ * vkms_connector_hot_remove() - Remove a connector after a device is created
+ * @vkmsdev: Device to containing the connector to be removed
+ * @connector: The connector to hot-remove
+ */
+void vkms_connector_hot_remove(struct vkms_device *vkmsdev,
+			       struct vkms_connector *connector);
+
+/**
+ * vkms_connector_hot_attach_encoder() - Attach a connector to a encoder after
+ * the device is created.
+ * @vkmsdev: Device containing the connector and the encoder
+ * @connector: Connector to attach to @encoder
+ * @encoder: Target encoder
+ *
+ * Returns:
+ * 0 on success or an error on failure.
+ */
+int vkms_connector_hot_attach_encoder(struct vkms_device *vkmsdev,
+				      struct vkms_connector *connector,
+				      struct drm_encoder *encoder);
+
 #endif /* _VKMS_CONNECTOR_H_ */
diff --git a/drivers/gpu/drm/vkms/vkms_output.c b/drivers/gpu/drm/vkms/vkms_output.c
index 13c4ca5fd39d..50f7d88dee8b 100644
--- a/drivers/gpu/drm/vkms/vkms_output.c
+++ b/drivers/gpu/drm/vkms/vkms_output.c
@@ -117,5 +117,14 @@ int vkms_output_init(struct vkms_device *vkmsdev)
 
 	drm_mode_config_reset(dev);
 
+	vkms_config_for_each_connector_dynamic(vkmsdev->config, connector_cfg) {
+		if (connector_cfg->enabled) {
+			connector_cfg->connector = vkms_connector_hot_add(vkmsdev, connector_cfg);
+
+			if (IS_ERR(connector_cfg->connector))
+				return PTR_ERR(connector_cfg->connector);
+		}
+	}
+
 	return 0;
 }

-- 
2.51.2

[PATCH v3 33/33] drm/vkms: Introduce configfs for dynamic connector creation

[Louis Chauvet]

DRM allows the connector to be created after the device. To allows
emulating this, add two configfs attributes to connector to allows this.

Using the dynamic attribute you can set if a connector will be dynamic or
not.
Using the enabled attribute, you can set at runtime if a dynamic connector
is present or not.

Co-developed-by: José Expósito <jose.exposito89@gmail.com>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 Documentation/ABI/testing/configfs-vkms |  14 +++
 Documentation/gpu/vkms.rst              |   6 +-
 drivers/gpu/drm/vkms/vkms_configfs.c    | 146 ++++++++++++++++++++++++++++++--
 3 files changed, 155 insertions(+), 11 deletions(-)

diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
index 4061ada5d88b..a7fce35fcf91 100644
--- a/Documentation/ABI/testing/configfs-vkms
+++ b/Documentation/ABI/testing/configfs-vkms
@@ -62,6 +62,20 @@ Description:
         Content of the EDID for this connector. Ignored if
         edid_enabled is not set.
 
+What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/dynamic
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        Set to 1 to create a dynamic connector (emulates DP MST).
+        Value: 1 - dynamic, 0 - static.
+
+What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/enabled
+Date:		Nov 2025
+Contact:	dri-devel@lists.freedesktop.org
+Description:
+        For dynamic connectors, set to 1 to create the connector,
+        0 to remove it. Value: 1 - enabled, 0 - disabled.
+
 What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/possible_encoders
 Date:		Nov 2025
 Contact:	dri-devel@lists.freedesktop.org
diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index 60367fd1bd65..fce229fbfc7c 100644
--- a/Documentation/gpu/vkms.rst
+++ b/Documentation/gpu/vkms.rst
@@ -138,7 +138,7 @@ Last but not least, create one or more connectors::
 
   sudo mkdir /config/vkms/my-vkms/connectors/connector0
 
-Connectors have 5 configurable attribute:
+Connectors have 7 configurable attribute:
 
 - status: Connection status: 1 connected, 2 disconnected, 3 unknown (same values
   as those exposed by the "status" property of a connector)
@@ -150,7 +150,9 @@ Connectors have 5 configurable attribute:
 - edid_enabled: Enable or not EDID for this connector. Some connectors may not have an
   EDID but just a list of modes, this attribute allows to disable EDID property.
 - edid: Content of the EDID. Ignored if edid_enabled is not set
-
+- dynamic: Set to 1 while configuring the device to create a dynamic connector. A dynamic
+  connector can be used to emulate DP MST connectors.
+- enabled: For dynamic connector, set it to 1 to create the connector, 0 to remove it.
 
 To finish the configuration, link the different pipeline items::
 
diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
index 20f5150e8b24..657381a8a4c2 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -1144,6 +1144,12 @@ static ssize_t connector_status_show(struct config_item *item, char *page)
 	return sprintf(page, "%u", status);
 }
 
+static bool connector_is_enabled(struct vkms_config_connector *connector_cfg)
+{
+	return !connector_cfg->dynamic ||
+	       (connector_cfg->dynamic && connector_cfg->enabled);
+}
+
 static ssize_t connector_status_store(struct config_item *item,
 				      const char *page, size_t count)
 {
@@ -1163,7 +1169,7 @@ static ssize_t connector_status_store(struct config_item *item,
 	scoped_guard(mutex, &connector->dev->lock) {
 		vkms_config_connector_set_status(connector->config, status);
 
-		if (connector->dev->enabled)
+		if (connector->dev->enabled && connector_is_enabled(connector->config))
 			vkms_trigger_connector_hotplug(connector->dev->config->dev);
 	}
 
@@ -1224,7 +1230,7 @@ static ssize_t connector_type_store(struct config_item *item,
 	}
 
 	scoped_guard(mutex, &connector->dev->lock) {
-		if (connector->dev->enabled)
+		if (connector->dev->enabled && connector_is_enabled(connector->config))
 			return -EBUSY;
 
 		vkms_config_connector_set_type(connector->config, val);
@@ -1343,6 +1349,107 @@ static ssize_t connector_edid_store(struct config_item *item,
 		    connector_status_disconnected)
 			vkms_trigger_connector_hotplug(connector->dev->config->dev);
 	}
+	return count;
+}
+
+static ssize_t connector_enabled_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_connector *connector;
+	bool enabled;
+
+	connector = connector_item_to_vkms_configfs_connector(item);
+
+	scoped_guard(mutex, &connector->dev->lock)
+		enabled = vkms_config_connector_is_enabled(connector->config);
+
+	return sprintf(page, "%d\n", enabled);
+}
+
+static ssize_t connector_enabled_store(struct config_item *item,
+				       const char *page, size_t count)
+{
+	struct vkms_configfs_connector *connector;
+	struct vkms_config_connector *connector_cfg;
+	bool enabled, was_enabled;
+
+	connector = connector_item_to_vkms_configfs_connector(item);
+	connector_cfg = connector->config;
+
+	if (kstrtobool(page, &enabled))
+		return -EINVAL;
+	scoped_guard(mutex, &connector->dev->lock) {
+		if (!connector->dev->enabled) {
+			vkms_config_connector_set_enabled(connector_cfg, enabled);
+		} else {
+			// Only dynamic connector can be enabled/disabled at runtime
+			if (!connector_cfg->dynamic)
+				return -EBUSY;
+
+			was_enabled = vkms_config_connector_is_enabled(connector_cfg);
+			vkms_config_connector_set_enabled(connector_cfg, enabled);
+
+			// Resulting configuration is invalid (missing encoder for example)
+			// Early return to avoid drm core issue
+			if (!vkms_config_is_valid(connector->dev->config)) {
+				count = -EINVAL;
+				goto rollback;
+			}
+
+			if (!was_enabled && enabled) {
+				// Adding the connector
+				connector_cfg->connector = vkms_connector_hot_add(connector->dev->config->dev,
+										  connector_cfg);
+				if (IS_ERR(connector_cfg->connector)) {
+					count = PTR_ERR(connector_cfg->connector);
+					goto rollback;
+				}
+			} else if (was_enabled && !enabled) {
+				vkms_connector_hot_remove(connector->dev->config->dev,
+							  connector_cfg->connector);
+			}
+		}
+	}
+	return count;
+
+rollback:
+	vkms_config_connector_set_enabled(connector_cfg, was_enabled);
+	return count;
+}
+
+static ssize_t connector_dynamic_show(struct config_item *item, char *page)
+{
+	struct vkms_configfs_connector *connector;
+	bool enabled;
+
+	connector = connector_item_to_vkms_configfs_connector(item);
+
+	scoped_guard(mutex, &connector->dev->lock) {
+		enabled = vkms_config_connector_is_dynamic(connector->config);
+	}
+
+	return sprintf(page, "%d\n", enabled);
+}
+
+static ssize_t connector_dynamic_store(struct config_item *item,
+				       const char *page, size_t count)
+{
+	struct vkms_configfs_connector *connector;
+	struct vkms_config_connector *connector_cfg;
+	bool dynamic;
+
+	connector = connector_item_to_vkms_configfs_connector(item);
+	connector_cfg = connector->config;
+
+	if (kstrtobool(page, &dynamic))
+		return -EINVAL;
+
+	scoped_guard(mutex, &connector->dev->lock) {
+		// Can't change the dynamic status when the device is activated
+		if (connector->dev->enabled)
+			return -EBUSY;
+
+		vkms_config_connector_set_dynamic(connector_cfg, dynamic);
+	}
 
 	return count;
 }
@@ -1352,6 +1459,8 @@ CONFIGFS_ATTR(connector_, type);
 CONFIGFS_ATTR(connector_, supported_colorspaces);
 CONFIGFS_ATTR(connector_, edid_enabled);
 CONFIGFS_ATTR(connector_, edid);
+CONFIGFS_ATTR(connector_, dynamic);
+CONFIGFS_ATTR(connector_, enabled);
 
 static struct configfs_attribute *connector_item_attrs[] = {
 	&connector_attr_status,
@@ -1359,19 +1468,28 @@ static struct configfs_attribute *connector_item_attrs[] = {
 	&connector_attr_supported_colorspaces,
 	&connector_attr_edid_enabled,
 	&connector_attr_edid,
+	&connector_attr_dynamic,
+	&connector_attr_enabled,
 	NULL,
 };
 
 static void connector_release(struct config_item *item)
 {
 	struct vkms_configfs_connector *connector;
+	struct vkms_config_connector *connector_cfg;
 	struct mutex *lock;
 
 	connector = connector_item_to_vkms_configfs_connector(item);
+	connector_cfg = connector->config;
 	lock = &connector->dev->lock;
 
 	scoped_guard(mutex, lock) {
+		if (connector->dev->enabled && connector_cfg->dynamic && connector_cfg->enabled)
+			vkms_connector_hot_remove(connector->dev->config->dev,
+						  connector_cfg->connector);
+
 		vkms_config_destroy_connector(connector->config);
+
 		kfree(connector);
 	}
 }
@@ -1390,6 +1508,7 @@ static int connector_possible_encoders_allow_link(struct config_item *src,
 						  struct config_item *target)
 {
 	struct vkms_configfs_connector *connector;
+	struct vkms_config_connector *connector_cfg;
 	struct vkms_configfs_encoder *encoder;
 	int ret;
 
@@ -1397,16 +1516,26 @@ static int connector_possible_encoders_allow_link(struct config_item *src,
 		return -EINVAL;
 
 	connector = connector_possible_encoders_item_to_vkms_configfs_connector(src);
+	connector_cfg = connector->config;
 	encoder = encoder_item_to_vkms_configfs_encoder(target);
 
 	scoped_guard(mutex, &connector->dev->lock) {
-		if (connector->dev->enabled)
-			return -EBUSY;
+		if (connector->dev->enabled && connector_cfg->enabled) {
+			if (!connector_cfg->dynamic)
+				return -EBUSY;
+
+			ret = vkms_connector_hot_attach_encoder(connector->dev->config->dev,
+								connector->config->connector,
+								encoder->config->encoder);
+			if (ret)
+				return ret;
+		}
 
 		ret = vkms_config_connector_attach_encoder(connector->config,
 							   encoder->config);
+		if (ret)
+			return ret;
 	}
-
 	return ret;
 }
 
@@ -1445,9 +1574,6 @@ static struct config_group *make_connector_group(struct config_group *group,
 	dev = child_group_to_vkms_configfs_device(group);
 
 	scoped_guard(mutex, &dev->lock) {
-		if (dev->enabled)
-			return ERR_PTR(-EBUSY);
-
 		connector = kzalloc(sizeof(*connector), GFP_KERNEL);
 		if (!connector)
 			return ERR_PTR(-ENOMEM);
@@ -1461,9 +1587,11 @@ static struct config_group *make_connector_group(struct config_group *group,
 			return ERR_PTR(ret);
 		}
 
+		vkms_config_connector_set_dynamic(connector->config, connector->dev->enabled);
+		vkms_config_connector_set_enabled(connector->config, !connector->dev->enabled);
+
 		config_group_init_type_name(&connector->group, name,
 					    &connector_item_type);
-
 		config_group_init_type_name(&connector->possible_encoders_group,
 					    "possible_encoders",
 					    &connector_possible_encoders_group_type);

-- 
2.51.2

Re: [PATCH v3 18/33] drm/vkms: Introduce configfs for plane format

[kernel test robot]

Hi Louis,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 8e7460eac786c72f48c4e04ce9be692b939428ce]

url:    https://github.com/intel-lab-lkp/linux/commits/Louis-Chauvet/Documentation-ABI-vkms-Add-current-VKMS-ABI-documentation/20251222-181426
base:   8e7460eac786c72f48c4e04ce9be692b939428ce
patch link:    https://lore.kernel.org/r/20251222-vkms-all-config-v3-18-ba42dc3fb9ff%40bootlin.com
patch subject: [PATCH v3 18/33] drm/vkms: Introduce configfs for plane format
config: i386-randconfig-141-20251223 (https://download.01.org/0day-ci/archive/20251223/202512230638.scAuFLVV-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251223/202512230638.scAuFLVV-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202512230638.scAuFLVV-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> Warning: drivers/gpu/drm/vkms/vkms_configfs.c:676 expecting prototype for parse_next_format(). Prototype was for vkms_configfs_parse_next_format() instead

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v3 18/33] drm/vkms: Introduce configfs for plane format

[kernel test robot]

Hi Louis,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 8e7460eac786c72f48c4e04ce9be692b939428ce]

url:    https://github.com/intel-lab-lkp/linux/commits/Louis-Chauvet/Documentation-ABI-vkms-Add-current-VKMS-ABI-documentation/20251222-181426
base:   8e7460eac786c72f48c4e04ce9be692b939428ce
patch link:    https://lore.kernel.org/r/20251222-vkms-all-config-v3-18-ba42dc3fb9ff%40bootlin.com
patch subject: [PATCH v3 18/33] drm/vkms: Introduce configfs for plane format
config: x86_64-rhel-9.4 (https://download.01.org/0day-ci/archive/20251223/202512230158.yEDymogC-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251223/202512230158.yEDymogC-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202512230158.yEDymogC-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> Warning: drivers/gpu/drm/vkms/vkms_configfs.c:676 expecting prototype for parse_next_format(). Prototype was for vkms_configfs_parse_next_format() instead

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v3 00/33] VKMS: Introduce multiple configFS attributes

[Luca Ceresoli]

On Mon Dec 22, 2025 at 11:11 AM CET, Louis Chauvet wrote:
> VKMS have a wide range of options. The aim of this series is to introduce
> many configfs attribute so VKMS can be used to test a wide range of
> configurations.
>
> PATCH 1,7,10,13,23 are to expose human readable strings from drm core
> PATCH 2-4 are to expose human readable plane type in debugfs
> PATCH 5,6 plane attribute
> PATCH 8,9 plane rotation
> PATCH 11,12 plane color encoding
> PATCH 14,15 plane color range
> PATCH 16,17 plane format
> PATCH 18 properly use zpos
> PATCH 19,20 plane zpos
> PATCH 21,22 connector type
> PATCH 24,25 connector supported colorspace
> PATCH 26,27 connector EDID
> PATCH 28,29 preparatory work for dynamic connectors
> PATCH 30,31 dynamic connectors
>
> PS: Each pair of config/configfs patch are independant. I could
> technically create ≈10 different series, but there will be a lot of
> (trivial) conflicts between them. I will be happy to reordoer, split and
> partially apply this series to help the review process.
>
> PS2: I will apply the patches 1..5 after my holidays, they are reviewed
> twice.

Be careful: as of now, patch 1 is not reviewed (it's new in v3) and patch 2
is reviewed once. I'm going to review this series however, so the count
will hopefully change soon. :)

Luca

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH v3 01/33] Documentation: ABI: vkms: Add current VKMS ABI documentation

[Luca Ceresoli]

On Mon Dec 22, 2025 at 11:11 AM CET, Louis Chauvet wrote:
> VKMS recently introduced a ConfigFS API to configure new devices.
> Add proper ABI documentation.
>
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>

> +++ b/Documentation/ABI/testing/configfs-vkms
> @@ -0,0 +1,118 @@
> +What:		/sys/kernel/config/vkms/
> +Date:		Nov 2025
> +Contact:	dri-devel@lists.freedesktop.org
> +Description:
> +        This group contains sub-groups corresponding to created
> +		VKMS devices.

Some lines use spaces for indentation, some use tabs. The two above lines
are an example, but this happens elsewhere in this patch.

With that fixed to be consistent:
 Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH v3 02/33] drm/drm_mode_config: Add helper to get plane type name

[Luca Ceresoli]

On Mon Dec 22, 2025 at 11:11 AM CET, Louis Chauvet wrote:
> Create and export an helper to display plane type using the
> property string. This could be used to display debug
> information in VKMS.
>
> Reviewed-by: José Expósito <jose.exposito@redhat.com>
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> ---
>  drivers/gpu/drm/drm_mode_config.c | 16 ++++++++++++++++
>  include/drm/drm_mode_config.h     |  3 +++
>  2 files changed, 19 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
> index d12db9b0bab8..c940a67e255b 100644
> --- a/drivers/gpu/drm/drm_mode_config.c
> +++ b/drivers/gpu/drm/drm_mode_config.c
> @@ -231,6 +231,22 @@ static const struct drm_prop_enum_list drm_plane_type_enum_list[] = {
>  	{ DRM_PLANE_TYPE_CURSOR, "Cursor" },
>  };
>
> +/**
> + * drm_get_plane_type_name - return a string for plane name
> + * @type: plane type to compute name of
> + *
> + * Returns: The name of the plane type. "(unknown)" if type is not a known
> + * plane type.
> + */
> +const char *drm_get_plane_type_name(enum drm_plane_type type)
> +{
> +	if (type > 0 && type < ARRAY_SIZE(drm_plane_type_enum_list))
This should be:  >= 0

With that fixed:

 Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH v3 06/33] drm/vkms: Introduce config for plane name

[Luca Ceresoli]

On Mon Dec 22, 2025 at 11:11 AM CET, Louis Chauvet wrote:
> As planes can have a name in DRM, prepare VKMS to configure it using
> ConfigFS.
>
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH v3 07/33] drm/vkms: Introduce configfs for plane name

[Luca Ceresoli]

On Mon Dec 22, 2025 at 11:11 AM CET, Louis Chauvet wrote:
> Planes can have name, create a plane attribute to configure it. Currently
> plane name is mainly used in logs.
>
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> ---
>  Documentation/ABI/testing/configfs-vkms |  6 +++++
>  Documentation/gpu/vkms.rst              |  3 ++-
>  drivers/gpu/drm/vkms/vkms_configfs.c    | 43 +++++++++++++++++++++++++++++++++
>  3 files changed, 51 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
> index 0beaa25f30ba..6fe375d1636f 100644
> --- a/Documentation/ABI/testing/configfs-vkms
> +++ b/Documentation/ABI/testing/configfs-vkms
> @@ -103,6 +103,12 @@ Description:
>          Plane type. Possible values: 0 - overlay, 1 - primary,
>          2 - cursor.
>
> +What:		/sys/kernel/config/vkms/<device>/planes/<plane>/name
> +Date:		Nov 2025
> +Contact:	dri-devel@lists.freedesktop.org
> +Description:
> +        Name of the plane.
> +
>  What:		/sys/kernel/config/vkms/<device>/planes/<plane>/possible_crtcs
>  Date:		Nov 2025
>  Contact:	dri-devel@lists.freedesktop.org
> diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
> index 1e79e62a6bc4..79f1185d8645 100644
> --- a/Documentation/gpu/vkms.rst
> +++ b/Documentation/gpu/vkms.rst
> @@ -87,10 +87,11 @@ Start by creating one or more planes::
>
>    sudo mkdir /config/vkms/my-vkms/planes/plane0
>
> -Planes have 1 configurable attribute:
> +Planes have 2 configurable attributes:
>
>  - type: Plane type: 0 overlay, 1 primary, 2 cursor (same values as those
>    exposed by the "type" property of a plane)
> +- name: Name of the plane. Allowed characters are [A-Za-z1-9_-]
>
>  Continue by creating one or more CRTCs::
>
> diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
> index 506666e21c91..989788042191 100644
> --- a/drivers/gpu/drm/vkms/vkms_configfs.c
> +++ b/drivers/gpu/drm/vkms/vkms_configfs.c
> @@ -324,10 +324,53 @@ static ssize_t plane_type_store(struct config_item *item, const char *page,
>  	return (ssize_t)count;
>  }
>
> +static ssize_t plane_name_show(struct config_item *item, char *page)
> +{
> +	struct vkms_configfs_plane *plane;
> +	const char *name;
> +
> +	plane = plane_item_to_vkms_configfs_plane(item);
> +
> +	scoped_guard(mutex, &plane->dev->lock)
> +		name = vkms_config_plane_get_name(plane->config);

vkms_config_plane_get_name() returns a pointer to the name string, not a
copy. Unless I'm missing something, that string might be freed before the
next lines, where it is used:

> +
> +	if (name)
> +		return sprintf(page, "%s\n", name);
> +	return sprintf(page, "\n");

So for safety the above 3 lines whould go inside the scoped_guard().

> +}
> +
> +static ssize_t plane_name_store(struct config_item *item, const char *page,
> +				size_t count)
> +{
> +	struct vkms_configfs_plane *plane;
> +	size_t str_len;
> +
> +	plane = plane_item_to_vkms_configfs_plane(item);
> +
> +	// strspn is not lenght-protected, ensure that page is a null-terminated string.
> +	str_len = strnlen(page, count);
> +	if (str_len >= count)
> +		return -EINVAL;
> +
> +	if (strspn(page, "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_-") != count - 1)
> +		return -EINVAL;

I see you effor to make this as clean as possible, thanks. Still this is a
tad ugly, and should be moved to some common place at some point IMO. For
now it's fine, but if you need to add more user-passed strings, that could
be the moment to move this code.

Luca

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH v3 10/33] drm/vkms: Introduce configfs for plane rotation

[Luca Ceresoli]

On Mon Dec 22, 2025 at 11:11 AM CET, Louis Chauvet wrote:
> To allows the userspace to test many hardware configurations, introduce a
> new interface to configure the available rotation per planes. VKMS
> supports any rotation and reflection, so the userspace can choose any
> combination.
>
> The supported rotations are configured by writing a rotation bitmask to
> the file `supported_rotations` and the default rotation is chosen by
> writing a rotation bitmask to `default_rotation`.
>
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>

> --- a/drivers/gpu/drm/vkms/vkms_configfs.c
> +++ b/drivers/gpu/drm/vkms/vkms_configfs.c
> @@ -365,24 +365,105 @@ static ssize_t plane_name_store(struct config_item *item, const char *page,
>  	return (ssize_t)count;
>  }
>
> +static ssize_t plane_supported_rotations_show(struct config_item *item, char *page)
> +{
> +	struct vkms_configfs_plane *plane;
> +	unsigned int plane_supported_rotations;
> +
> +	plane = plane_item_to_vkms_configfs_plane(item);

You seem to have missed "assign on declaration" here (but you did it in
plane_default_rotation_show()).

The code added w.r.t. v2 looks OK as well, so with the above nit fixed:

 Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH v3 13/33] drm/vkms: Introduce configfs for plane color encoding

[Luca Ceresoli]

On Mon Dec 22, 2025 at 11:11 AM CET, Louis Chauvet wrote:
> To allows the userspace to test many hardware configuration, introduce a
> new interface to configure the available color encoding per planes. VKMS
> supports multiple color encoding, so the userspace can choose any
> combination.
>
> The supported color encoding are configured by writing a color encoding
> bitmask to the file `supported_color_encoding` and the default color
> encoding is chosen by writing a color encoding bitmask to
> `default_color_encoding`.
>
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>

> --- a/Documentation/ABI/testing/configfs-vkms
> +++ b/Documentation/ABI/testing/configfs-vkms
> @@ -124,6 +124,20 @@ Description:
>          Default rotation presented to userspace, same values as
>          possible_rotations.
>
> +What:		/sys/kernel/config/vkms/<device>/planes/<plane>/supported_color_encoding
                                                                                        ^
supported_color_encodings (final 's').

> --- a/Documentation/gpu/vkms.rst
> +++ b/Documentation/gpu/vkms.rst

> +static ssize_t plane_supported_color_encodings_store(struct config_item *item,
> +						     const char *page, size_t count)
> +{
> +	struct vkms_configfs_plane *plane = plane_item_to_vkms_configfs_plane(item);
> +	int ret, val = 0;
> +
> +	ret = kstrtouint(page, 10, &val);
> +	if (ret)
> +		return ret;
> +
> +	/* Should be a supported value */
> +	if (val & ~(VKMS_SUPPORTED_COLOR_ENCODINGS))
> +		return -EINVAL;
> +	/* Should at least provide one color range */
                                             ^ encoding

> +static ssize_t plane_default_color_encoding_show(struct config_item *item, char *page)
> +{
> +	struct vkms_configfs_plane *plane;
> +	unsigned int default_color_encoding;
> +
> +	plane = plane_item_to_vkms_configfs_plane(item);

Set on declare, for consistency (and conciseness).

> +static ssize_t plane_default_color_encoding_store(struct config_item *item,
> +						  const char *page, size_t count)
> +{
> +	struct vkms_configfs_plane *plane = plane_item_to_vkms_configfs_plane(item);
> +	int ret, val = 0;
> +
> +	ret = kstrtouint(page, 10, &val);
> +	if (ret)
> +		return ret;
> +
> +	/* Should be a supported value */
> +	if (val & ~VKMS_SUPPORTED_COLOR_ENCODINGS)
> +		return -EINVAL;
> +	/* Should at least provide one color range */
> +	if ((val & VKMS_SUPPORTED_COLOR_ENCODINGS) == 0)
> +		return -EINVAL;

This if() is redundant, the is_power_of_2() implies it because you already
ruled out any unsupported bit. Also, the comment is wrong. You can drop
these 3 lines entirely.

Luca

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH v3 18/33] drm/vkms: Introduce configfs for plane format

[kernel test robot]

Hi Louis,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 8e7460eac786c72f48c4e04ce9be692b939428ce]

url:    https://github.com/intel-lab-lkp/linux/commits/Louis-Chauvet/Documentation-ABI-vkms-Add-current-VKMS-ABI-documentation/20251222-181426
base:   8e7460eac786c72f48c4e04ce9be692b939428ce
patch link:    https://lore.kernel.org/r/20251222-vkms-all-config-v3-18-ba42dc3fb9ff%40bootlin.com
patch subject: [PATCH v3 18/33] drm/vkms: Introduce configfs for plane format
reproduce: (https://download.01.org/0day-ci/archive/20251223/202512231419.lVidy4qV-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202512231419.lVidy4qV-lkp@intel.com/

All warnings (new ones prefixed by >>):

   Using alabaster theme
   ERROR: Cannot find file ./include/linux/pci.h
   WARNING: No kernel-doc for file ./include/linux/pci.h
   ERROR: Cannot find file ./include/linux/mod_devicetable.h
   WARNING: No kernel-doc for file ./include/linux/mod_devicetable.h
>> Documentation/ABI/testing/configfs-vkms:156: WARNING: Inline emphasis start-string without end-string. [docutils]
   ERROR: Cannot find file ./include/linux/bootconfig.h
   WARNING: No kernel-doc for file ./include/linux/bootconfig.h
   ERROR: Cannot find file ./include/linux/pstore_zone.h
   ERROR: Cannot find file ./include/linux/pstore_zone.h
   WARNING: No kernel-doc for file ./include/linux/pstore_zone.h


vim +156 Documentation/ABI/testing/configfs-vkms

 > 156	What:		/sys/kernel/config/vkms/<device>/planes/<plane>/supported_formats
   157	Date:		Nov 2025
   158	Contact:	dri-devel@lists.freedesktop.org
   159	Description:
   160	        List of supported formats for this plane. To add a new
   161	        item, write its fourcc code prefixed with '+'. To remove,
   162	        use '-' prefix. Use '+*' to add all formats, '-*' to
   163	        remove all.
   164	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v3 16/33] drm/vkms: Introduce configfs for plane color range

[Luca Ceresoli]

On Mon Dec 22, 2025 at 11:11 AM CET, Louis Chauvet wrote:
> To allows the userspace to test many hardware configuration, introduce a
> new interface to configure the available color ranges per planes. VKMS
> supports multiple color ranges, so the userspace can choose any
> combination.
>
> The supported color ranges are configured by writing a color range bitmask
> to the file `supported_color_ranges` and the default color range is
> chosen by writing a color encoding bitmask to `default_color_range`.
>
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>

> --- a/Documentation/ABI/testing/configfs-vkms
> +++ b/Documentation/ABI/testing/configfs-vkms
> @@ -138,6 +138,21 @@ Description:
>          Default color encoding presented to userspace, same
>          values as supported_color_encoding.
>
> +What:		/sys/kernel/config/vkms/<device>/planes/<plane>/supported_color_ranges
> +Date:		Nov 2025

This should be Jan 2026 I guess. Same for the previous patches in the
series which I already reviewed, sorry I didn't notice before.

BTW I wonder whether it is really important to have a date here. The time
before a patch is applied can make it quite wrong, but mostly I don't see
an obvious usefulness.

> --- a/drivers/gpu/drm/vkms/vkms_configfs.c
> +++ b/drivers/gpu/drm/vkms/vkms_configfs.c

> +static ssize_t plane_default_color_range_show(struct config_item *item, char *page)
> +{
> +	struct vkms_configfs_plane *plane = plane_item_to_vkms_configfs_plane(item);;

Double semicolon.

> +static ssize_t plane_default_color_range_store(struct config_item *item,
> +					       const char *page, size_t count)
> +{
> +	struct vkms_configfs_plane *plane = plane_item_to_vkms_configfs_plane(item);
> +	int ret, val = 0;
> +
> +	ret = kstrtouint(page, 10, &val);
> +	if (ret)
> +		return ret;
> +
> +	/* Should be a supported value */
> +	if (val & ~VKMS_SUPPORTED_COLOR_RANGES)
> +		return -EINVAL;
> +	/* Should at least provide one color range */
> +	if ((val & VKMS_SUPPORTED_COLOR_RANGES) == 0)
> +		return -EINVAL;

As for patch 13, these 3 lines are redundant, the is_power_of_2() below is
enough.

> +
> +	if (!is_power_of_2(val))
> +		return -EINVAL;
> +
> +	/* Convert bit position to the proper enum value */
> +	val = __ffs(val) + DRM_COLOR_YCBCR_LIMITED_RANGE;
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

I wonder whether this should just be '+ 1'. After all it's just the __ffs
semantics counting from 1 as opposed to the BIT() semantics counting from
0. Any pair of BIT() to read and __ffs() to write will need a '+ 1',
regardless of the meaning of the bits.

Same in patch 13, but realized just now.

Luca

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH v3 17/33] drm/vkms: Introduce config for plane format

[Luca Ceresoli]

On Mon Dec 22, 2025 at 11:11 AM CET, Louis Chauvet wrote:
> VKMS driver supports all the pixel formats for planes, but for testing it
> can be useful to only advertise few of them. This new configuration
> interface will allow configuring the pixel format per planes.
>
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>

> --- a/drivers/gpu/drm/vkms/vkms_config.c
> +++ b/drivers/gpu/drm/vkms/vkms_config.c

> +void vkms_config_plane_remove_all_formats(struct vkms_config_plane *plane_cfg)
> +{
> +	plane_cfg->supported_formats_count = 0;

Why not kfree(plane_cfg->supported_formats) too? You will be (re)allocating
anyway if adding one or all formats later on, so the buffer you're not
freeing won't be reused anyway.

> +}
> +
> +void vkms_config_plane_remove_format(struct vkms_config_plane *plane_cfg, u32 drm_format)
> +{
> +	for (unsigned int i = 0; i < plane_cfg->supported_formats_count; i++) {
> +		if (plane_cfg->supported_formats[i] == drm_format) {
> +			plane_cfg->supported_formats[i] = plane_cfg->supported_formats[plane_cfg->supported_formats_count - 1];

I doubt these are less than 100 chars. ;-)

> --- a/drivers/gpu/drm/vkms/vkms_config.h
> +++ b/drivers/gpu/drm/vkms/vkms_config.h
> @@ -49,6 +49,8 @@ struct vkms_config {
>   * @supported_color_encodings: Color encodings that this plane will support
>   * @default_color_range: Default color range that should be used by this plane
>   * @supported_color_ranges: Color ranges that this plane will support
> + * @supported_formats: List of supported formats
> + * @supported_formats_count: Length of @supported_formats

Nitpick: this description is not adding much. "Number of elements in
@supported_formats" would be more useful, as it would clarify it's number
of (4-bytes) elements and not size in bytes.

> +int __must_check vkms_config_plane_add_format(struct vkms_config_plane *plane_cfg, u32 drm_format);
> +
> +/**
> + * vkms_config_plane_add_all_formats - Helper to quickly add all the supported formats
> + * @plane_cfg: Plane to add the formats to
> + *
> + * Returns: 0 on success, -ENOMEM if array allocation fails, -EINVAL if the format is not supported
> + * by VKMS

The "-EINVAL ... VKMS" part of the sentence does not apply here.

> +/**
> + * vkms_config_plane_remove_format - Remove a specific format from a plane
> + * @plane_cfg: Plane to remove the format to
                                             ^^ from

Luca

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH v3 18/33] drm/vkms: Introduce configfs for plane format

[Luca Ceresoli]

On Mon Dec 22, 2025 at 11:11 AM CET, Louis Chauvet wrote:
> To allow the userspace to test many hardware configuration, introduce a
> new interface to configure the available formats per planes. VKMS supports
> multiple formats, so the userspace can choose any combination.
>
> The supported formats are configured by writing the fourcc code in
> supported_formats:
>  # enable AR24 format
>   echo '+AR24' > /config/vkms/DEVICE_1/planes/PLANE_1/supported_formats
>  # disable AR24 format
>   echo '-AR24' > /config/vkms/DEVICE_1/planes/PLANE_1/supported_formats
>  # enable all format supported by VKMS
>   echo '+*' > /config/vkms/DEVICE_1/planes/PLANE_1/supported_formats
>  # disable all formats
>   echo '-*' > /config/vkms/DEVICE_1/planes/PLANE_1/supported_formats
>
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>

> --- a/Documentation/ABI/testing/configfs-vkms
> +++ b/Documentation/ABI/testing/configfs-vkms
> @@ -153,6 +153,15 @@ Description:
>          Default color range presented to userspace, same
>          values as supported_color_ranges.
>
> +What:		/sys/kernel/config/vkms/<device>/planes/<plane>/supported_formats
> +Date:		Nov 2025

Jan 2026.

> --- a/Documentation/gpu/vkms.rst
> +++ b/Documentation/gpu/vkms.rst
> @@ -87,7 +87,7 @@ Start by creating one or more planes::
>
>    sudo mkdir /config/vkms/my-vkms/planes/plane0
>
> -Planes have 8 configurable attributes:
> +Planes have 9 configurable attributes:
>
>  - type: Plane type: 0 overlay, 1 primary, 2 cursor (same values as those
>    exposed by the "type" property of a plane)
> @@ -109,6 +109,11 @@ Planes have 8 configurable attributes:
>    must be set too.
>  - default_color_range: Default color range presented to the userspace, same
>    values as supported_color_ranges
> +- supported_formats: List of supported formats for this plane. To add a new item in the
> +  list, write it using a plus and fourcc code: +XR24
> +  To remove a format, use a minus and its fourcc: -XR24

From the docs examples it's not obvious that you can add/remove multiple
formats in one write operation ("+XR24 -RG24"), but the implementation
allows it. So either add a more complete example or forbid multiple
operations in one write. I would consider the latter option seriously
because it would simplify the string parsing code, which is very tricky to
get right and robust.

> +++ b/drivers/gpu/drm/vkms/tests/vkms_configfs_test.c
> @@ -0,0 +1,102 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +
> +#include "linux/printk.h"
> +#include <kunit/test.h>
> +
> +#include "../vkms_configfs.h"
> +
> +MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING");
> +
> +/**
> + * struct vkms_configfs_parse_format_case - Store test case for format parsing
> + * @str: Contains the string to parse
> + * @str_len: str len
> + * @expected_len: expected len of the matched format
> + * @expected_offset: expected offset in the string for the parsed format
> + */
> +struct vkms_configfs_parse_format_case {
> +	const char *str;
> +	int str_len;
> +	int expected_len;
> +	int expected_offset;
> +};
> +
> +struct vkms_configfs_parse_format_case vkms_configfs_parse_format_test_cases[] = {
> +	{
> +		.str = "+RG24",
> +		.str_len = 6,
> +		.expected_len = 5,
> +		.expected_offset = 0,

Thanks for having renamed 'data' to 'str'! However now I realize the
'str_len' name becomes misleading: the string length does not include the
training NUL character, while the value you need here does. I beg your
pardon... I guess 'str_len' should be renamed too, maybe to 'str_size' if
no better name comes to mind.

> +	}, {

Based on the question I asked after v3,resend and on your answer, I'd add a
clarifying comment here about the following test:

	   /* ensure the algorithm stops at data_len and not \0 */

> +		.str = "-R1111",
> +		.str_len = 3,
> +		.expected_len = 3,
> +		.expected_offset = 0
> +	}

Testing wrong and corner cases is more important than testing perfectly
clean cases. So it would be nice to add tests for not-obviously-wrong and
definitely-wrong cases, such as "+ RG24" (note the space), "fubar", "+**",
"*+", "++", "-+", "-A*42" (see below), ":-)" (dash after non-blank char)
and "(-o-)".

> --- a/drivers/gpu/drm/vkms/vkms_configfs.c
> +++ b/drivers/gpu/drm/vkms/vkms_configfs.c
> @@ -3,6 +3,8 @@
>  #include <linux/configfs.h>
>  #include <linux/mutex.h>
>  #include <linux/slab.h>
> +#include <linux/string.h>
> +#include <kunit/visibility.h>
>
>  #include "vkms_drv.h"
>  #include "vkms_config.h"
> @@ -628,6 +630,120 @@ static ssize_t plane_default_color_encoding_store(struct config_item *item,
>  	return count;
>  }
>
> +static ssize_t plane_supported_formats_show(struct config_item *item, char *page)
> +{
> +	struct vkms_configfs_plane *plane;
> +
> +	plane = plane_item_to_vkms_configfs_plane(item);
> +
> +	page[0] = '\0';
> +
> +	scoped_guard(mutex, &plane->dev->lock) {
> +		u32 *formats = vkms_config_plane_get_supported_formats(plane->config);
> +
> +		for (int i = 0;
> +		     i < vkms_config_plane_get_supported_formats_count(plane->config);
> +		     i++) {
> +			char tmp[6] = { 0 };
> +			const ssize_t ret = snprintf(tmp, ARRAY_SIZE(tmp), "%.*s\n",
> +					       (int)sizeof(*formats),
> +					       (char *)&formats[i]);
> +			if (ret < 0)
> +				return ret;
> +			/*
> +			 * Limitation of ConfigFS attributes, an attribute can't be bigger
> +			 * than PAGE_SIZE. This will crop the result if this plane support
> +			 * more than ≈1000 formats.

Every format takes 5 chars, so about 800 formats, no?

> +			 */
> +			if (ret + strlen(page) > PAGE_SIZE - 1)
> +				return -ENOMEM;
> +			strncat(page, tmp, ARRAY_SIZE(tmp));
> +		}
> +	}
> +
> +	return strlen(page);
> +}
> +
> +/**
> + * parse_next_format() - Parse the next format in page, skipping all non fourcc-related characters
> + * @page: page to search into
> + * @page_end: last character of the page
> + * @out: Output pointer, will point inside page
> + *
> + * Returns: size of the matched format, @out will point to the + or -
> + */
> +VISIBLE_IF_KUNIT
> +int vkms_configfs_parse_next_format(const char *page, const char *page_end, char **out)
> +{
> +	int count = page - page_end;
> +	char *tmp_plus = strnchr(page, count, '+');
> +	char *tmp_minus = strnchr(page, count, '-');
> +
> +	if (!tmp_plus && !tmp_minus)
> +		return 0;
> +	if (!tmp_plus)
> +		*out = tmp_minus;
> +	else if (!tmp_minus)
> +		*out = tmp_plus;
> +	else
> +		*out = min(tmp_plus, tmp_minus);
> +
> +	char *end = *out + 1;
> +
> +	while (end < page_end) {
> +		if (!isalnum(*end) && *end != '*')
> +			break;
> +		end++;
> +	}

I think this while loop will capture a string like "A*42", which is wrong.

Maybe you could change this function to be both stricter and simpler by not
trying to accept leading spaces, for example.

> +static ssize_t plane_supported_formats_store(struct config_item *item,
> +					     const char *page, size_t count)
> +{
> +	struct vkms_configfs_plane *plane;
> +
> +	plane = plane_item_to_vkms_configfs_plane(item);
> +	int ret = 0;
> +	const char *end_page = page + count;
> +
> +	scoped_guard(mutex, &plane->dev->lock) {
> +		while (1) {
> +			char *tmp;
> +			char fmt[4] = {' ', ' ', ' ', ' '};
> +			int len = vkms_configfs_parse_next_format(page, end_page, &tmp);
> +
> +			// No fourcc code found
> +			if (len <= 1 || len > 5)
> +				break;
> +
> +			page = tmp + len;
> +			memcpy(fmt, &tmp[1], min(len - 1, 4));
> +			if (tmp[0] == '+') {
> +				if (fmt[0] == '*') {
> +					ret = vkms_config_plane_add_all_formats(plane->config);
> +					if (ret)
> +						return ret;
> +				} else {
> +					ret = vkms_config_plane_add_format(plane->config,
> +									   *(int *)fmt);
> +					if (ret)
> +						return ret;
> +				}

Minor code simplification:

				if (fmt[0] == '*')
					ret = vkms_config_plane_add_all_formats(plane->config);
				else
					ret = vkms_config_plane_add_format(plane->config,
									   *(int *)fmt);
				if (ret)
					return ret;

Or, if you like the ternary operator:


				ret = (fmt[0] == '*') ?
					vkms_config_plane_add_all_formats(plane->config):
					vkms_config_plane_add_format(plane->config, *(int *)fmt);
				if (ret)
					return ret;

I'm sorry some of these comments could have been written asof v2, but this
patch is really intricate and they came to mind only while re-thinking
about the code.

Luca

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH v3 33/33] drm/vkms: Introduce configfs for dynamic connector creation

[Luca Ceresoli]

On Mon Dec 22, 2025 at 11:11 AM CET, Louis Chauvet wrote:
> DRM allows the connector to be created after the device. To allows
> emulating this, add two configfs attributes to connector to allows this.
>
> Using the dynamic attribute you can set if a connector will be dynamic or
> not.
> Using the enabled attribute, you can set at runtime if a dynamic connector
> is present or not.
>
> Co-developed-by: José Expósito <jose.exposito89@gmail.com>
> Signed-off-by: José Expósito <jose.exposito89@gmail.com>
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>

[...]

> +static ssize_t connector_dynamic_show(struct config_item *item, char *page)
> +{
> +	struct vkms_configfs_connector *connector;
> +	bool enabled;
             ^^^^^^^
	     dynamic

With that fixed:

 Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

Luca

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH v3 20/33] drm/vkms: Introduce config for plane zpos property

[Luca Ceresoli]

On Mon Dec 22, 2025 at 11:11 AM CET, Louis Chauvet wrote:
> VKMS can render plane in any order. Introduce the appropriate
> configuration.
>
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>

> @@ -253,6 +256,33 @@ bool vkms_config_valid_plane_color_range(const struct vkms_config *config,
>  }
>  EXPORT_SYMBOL_IF_KUNIT(vkms_config_valid_plane_color_range);
>
> +VISIBLE_IF_KUNIT
> +bool vkms_config_valid_plane_zpos(const struct vkms_config *config,
> +				  const struct vkms_config_plane *plane_cfg)
> +{
> +	struct drm_device *dev = config->dev ? &config->dev->drm : NULL;
> +
> +	if (!vkms_config_plane_get_zpos_enabled(plane_cfg) ||
> +	    !vkms_config_plane_get_zpos_mutable(plane_cfg))
> +		return true;
> +
> +	if (vkms_config_plane_get_zpos_initial(plane_cfg) >
> +	    vkms_config_plane_get_zpos_max(plane_cfg)) {
> +		drm_info(dev, "Configured initial zpos value bigger than zpos max\n");
> +		return false;
> +	}
> +
> +	if (vkms_config_plane_get_zpos_max(plane_cfg) <
> +	    vkms_config_plane_get_zpos_min(plane_cfg) ||
> +	    vkms_config_plane_get_zpos_initial(plane_cfg) <
> +	    vkms_config_plane_get_zpos_min(plane_cfg)) {
> +		drm_info(dev, "Configured zpos value outside (zpos min; zpos max)\n");
> +		return false;
> +	}

Weird grouping. It should rather be:

 if (max < min) {...}

 if (initial > max || initial < min) {...}

Luca

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH v3 18/33] drm/vkms: Introduce configfs for plane format

[Bagas Sanjaya]

[-- Attachment #1: Type: text/plain, Size: 1397 bytes --]

On Mon, Dec 22, 2025 at 11:11:20AM +0100, Louis Chauvet wrote:
> +What:		/sys/kernel/config/vkms/<device>/planes/<plane>/supported_formats
> +Date:		Nov 2025
> +Contact:	dri-devel@lists.freedesktop.org
> +Description:
> +        List of supported formats for this plane. To add a new
> +        item, write its fourcc code prefixed with '+'. To remove,
> +        use '-' prefix. Use '+*' to add all formats, '-*' to
> +        remove all.
> +

Sphinx reports htmldocs warning:

Documentation/ABI/testing/configfs-vkms:199: WARNING: Inline emphasis start-string without end-string. [docutils]

I have to escape the wildcard:

---- >8 ----
diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
index a7fce35fcf91d1..3839b6e3c9c935 100644
--- a/Documentation/ABI/testing/configfs-vkms
+++ b/Documentation/ABI/testing/configfs-vkms
@@ -202,7 +202,7 @@ Contact:	dri-devel@lists.freedesktop.org
 Description:
         List of supported formats for this plane. To add a new
         item, write its fourcc code prefixed with '+'. To remove,
-        use '-' prefix. Use '+*' to add all formats, '-*' to
+        use '-' prefix. Use '+*' to add all formats, '-\*' to
         remove all.
 
 What:		/sys/kernel/config/vkms/<device>/planes/<plane>/zpos_enabled

Thanks.

-- 
An old man doll... just what I always wanted! - Clara

[-- Attachment #2: signature.asc --]
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Re: [PATCH v3 07/33] drm/vkms: Introduce configfs for plane name

[Louis Chauvet]

On 12/23/25 12:14, Luca Ceresoli wrote:
> On Mon Dec 22, 2025 at 11:11 AM CET, Louis Chauvet wrote:
>> Planes can have name, create a plane attribute to configure it. Currently
>> plane name is mainly used in logs.
>>
>> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
>> ---
>>   Documentation/ABI/testing/configfs-vkms |  6 +++++
>>   Documentation/gpu/vkms.rst              |  3 ++-
>>   drivers/gpu/drm/vkms/vkms_configfs.c    | 43 +++++++++++++++++++++++++++++++++
>>   3 files changed, 51 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
>> index 0beaa25f30ba..6fe375d1636f 100644
>> --- a/Documentation/ABI/testing/configfs-vkms
>> +++ b/Documentation/ABI/testing/configfs-vkms
>> @@ -103,6 +103,12 @@ Description:
>>           Plane type. Possible values: 0 - overlay, 1 - primary,
>>           2 - cursor.
>>
>> +What:		/sys/kernel/config/vkms/<device>/planes/<plane>/name
>> +Date:		Nov 2025
>> +Contact:	dri-devel@lists.freedesktop.org
>> +Description:
>> +        Name of the plane.
>> +
>>   What:		/sys/kernel/config/vkms/<device>/planes/<plane>/possible_crtcs
>>   Date:		Nov 2025
>>   Contact:	dri-devel@lists.freedesktop.org
>> diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
>> index 1e79e62a6bc4..79f1185d8645 100644
>> --- a/Documentation/gpu/vkms.rst
>> +++ b/Documentation/gpu/vkms.rst
>> @@ -87,10 +87,11 @@ Start by creating one or more planes::
>>
>>     sudo mkdir /config/vkms/my-vkms/planes/plane0
>>
>> -Planes have 1 configurable attribute:
>> +Planes have 2 configurable attributes:
>>
>>   - type: Plane type: 0 overlay, 1 primary, 2 cursor (same values as those
>>     exposed by the "type" property of a plane)
>> +- name: Name of the plane. Allowed characters are [A-Za-z1-9_-]
>>
>>   Continue by creating one or more CRTCs::
>>
>> diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
>> index 506666e21c91..989788042191 100644
>> --- a/drivers/gpu/drm/vkms/vkms_configfs.c
>> +++ b/drivers/gpu/drm/vkms/vkms_configfs.c
>> @@ -324,10 +324,53 @@ static ssize_t plane_type_store(struct config_item *item, const char *page,
>>   	return (ssize_t)count;
>>   }
>>
>> +static ssize_t plane_name_show(struct config_item *item, char *page)
>> +{
>> +	struct vkms_configfs_plane *plane;
>> +	const char *name;
>> +
>> +	plane = plane_item_to_vkms_configfs_plane(item);
>> +
>> +	scoped_guard(mutex, &plane->dev->lock)
>> +		name = vkms_config_plane_get_name(plane->config);
> 
> vkms_config_plane_get_name() returns a pointer to the name string, not a
> copy. Unless I'm missing something, that string might be freed before the
> next lines, where it is used:
> 
>> +
>> +	if (name)
>> +		return sprintf(page, "%s\n", name);
>> +	return sprintf(page, "\n");
> 
> So for safety the above 3 lines whould go inside the scoped_guard().

Good catch!

This also raised some questions on the whole locking synchronization 
between configfs / config / DRM core. I will work on this topic and 
maybe move the mutex / add a refcount to vkms_config.

>> +}
>> +
>> +static ssize_t plane_name_store(struct config_item *item, const char *page,
>> +				size_t count)
>> +{
>> +	struct vkms_configfs_plane *plane;
>> +	size_t str_len;
>> +
>> +	plane = plane_item_to_vkms_configfs_plane(item);
>> +
>> +	// strspn is not lenght-protected, ensure that page is a null-terminated string.
>> +	str_len = strnlen(page, count);
>> +	if (str_len >= count)
>> +		return -EINVAL;
>> +
>> +	if (strspn(page, "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_-") != count - 1)
>> +		return -EINVAL;
> 
> I see you effor to make this as clean as possible, thanks. Still this is a
> tad ugly, and should be moved to some common place at some point IMO. For
> now it's fine, but if you need to add more user-passed strings, that could
> be the moment to move this code.

There are multiple "user strings" in this file (notably group names), 
but currently without limitation.

I can create a tiny helper and limit all user strings to a-zA-Z0-9_-
It will technically break the ABI, but I don't think this is a big issue.

Do you or José think this is a good idea? If so I can extract the helper 
for v4 and send a separate series to do the limitation on other strings.

> Luca
> 
> --
> Luca Ceresoli, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com

Re: [PATCH v3 17/33] drm/vkms: Introduce config for plane format

[Louis Chauvet]

On 12/23/25 14:58, Luca Ceresoli wrote:
> On Mon Dec 22, 2025 at 11:11 AM CET, Louis Chauvet wrote:
>> VKMS driver supports all the pixel formats for planes, but for testing it
>> can be useful to only advertise few of them. This new configuration
>> interface will allow configuring the pixel format per planes.
>>
>> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> 
>> --- a/drivers/gpu/drm/vkms/vkms_config.c
>> +++ b/drivers/gpu/drm/vkms/vkms_config.c
> 
>> +void vkms_config_plane_remove_all_formats(struct vkms_config_plane *plane_cfg)
>> +{
>> +	plane_cfg->supported_formats_count = 0;
> 
> Why not kfree(plane_cfg->supported_formats) too? You will be (re)allocating
> anyway if adding one or all formats later on, so the buffer you're not
> freeing won't be reused anyway.

IIRC realloc reuse the existing allocated buffer if it is big enough to fit the new
size. But I think this is probably an oversight here and I will add the free to clarify the situation :-)

>> +}
>> +
>> +void vkms_config_plane_remove_format(struct vkms_config_plane *plane_cfg, u32 drm_format)
>> +{
>> +	for (unsigned int i = 0; i < plane_cfg->supported_formats_count; i++) {
>> +		if (plane_cfg->supported_formats[i] == drm_format) {
>> +			plane_cfg->supported_formats[i] = plane_cfg->supported_formats[plane_cfg->supported_formats_count - 1];
> 
> I doubt these are less than 100 chars. ;-)

yes, 127, but I don't know how to format it so it is readable.

I tried

plane_cfg->supported_formats[i] =
	plane_cfg->supported_formats[plane_cfg->supported_formats_count - 1];

But the second line is 101 chars...

Checkpatch don't complain if I do:

plane_cfg->supported_formats[i] =
	plane_cfg->supported_formats[
		plane_cfg->supported_formats_count - 1];

or

plane_cfg->supported_formats[i] =
	plane_cfg->supported_formats[plane_cfg->supported_formats_count-
		1];

But that very ugly and not readable...

>> --- a/drivers/gpu/drm/vkms/vkms_config.h
>> +++ b/drivers/gpu/drm/vkms/vkms_config.h
>> @@ -49,6 +49,8 @@ struct vkms_config {
>>    * @supported_color_encodings: Color encodings that this plane will support
>>    * @default_color_range: Default color range that should be used by this plane
>>    * @supported_color_ranges: Color ranges that this plane will support
>> + * @supported_formats: List of supported formats
>> + * @supported_formats_count: Length of @supported_formats
> 
> Nitpick: this description is not adding much. "Number of elements in
> @supported_formats" would be more useful, as it would clarify it's number
> of (4-bytes) elements and not size in bytes.
> 
>> +int __must_check vkms_config_plane_add_format(struct vkms_config_plane *plane_cfg, u32 drm_format);
>> +
>> +/**
>> + * vkms_config_plane_add_all_formats - Helper to quickly add all the supported formats
>> + * @plane_cfg: Plane to add the formats to
>> + *
>> + * Returns: 0 on success, -ENOMEM if array allocation fails, -EINVAL if the format is not supported
>> + * by VKMS
> 
> The "-EINVAL ... VKMS" part of the sentence does not apply here.

True!

>> +/**
>> + * vkms_config_plane_remove_format - Remove a specific format from a plane
>> + * @plane_cfg: Plane to remove the format to
>                                               ^^ from
> 
> Luca
> 
> --
> Luca Ceresoli, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com

Re: [PATCH v3 18/33] drm/vkms: Introduce configfs for plane format

[Louis Chauvet]

On 12/25/25 01:59, Bagas Sanjaya wrote:
> On Mon, Dec 22, 2025 at 11:11:20AM +0100, Louis Chauvet wrote:
>> +What:		/sys/kernel/config/vkms/<device>/planes/<plane>/supported_formats
>> +Date:		Nov 2025
>> +Contact:	dri-devel@lists.freedesktop.org
>> +Description:
>> +        List of supported formats for this plane. To add a new
>> +        item, write its fourcc code prefixed with '+'. To remove,
>> +        use '-' prefix. Use '+*' to add all formats, '-*' to
>> +        remove all.
>> +
> 
> Sphinx reports htmldocs warning:
> 
> Documentation/ABI/testing/configfs-vkms:199: WARNING: Inline emphasis start-string without end-string. [docutils]
> 
> I have to escape the wildcard:
> 
> ---- >8 ----
> diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
> index a7fce35fcf91d1..3839b6e3c9c935 100644
> --- a/Documentation/ABI/testing/configfs-vkms
> +++ b/Documentation/ABI/testing/configfs-vkms
> @@ -202,7 +202,7 @@ Contact:	dri-devel@lists.freedesktop.org
>   Description:
>           List of supported formats for this plane. To add a new
>           item, write its fourcc code prefixed with '+'. To remove,
> -        use '-' prefix. Use '+*' to add all formats, '-*' to
> +        use '-' prefix. Use '+*' to add all formats, '-\*' to

Hi, thanks for the fix!

I only have to escape the second wildcard? Not the `+*`?

>           remove all.
>   
>   What:		/sys/kernel/config/vkms/<device>/planes/<plane>/zpos_enabled
> 
> Thanks.
> 

Re: [PATCH v3 07/33] drm/vkms: Introduce configfs for plane name

[José Expósito]

Hey Louis,

On Mon, Dec 22, 2025 at 11:11:09AM +0100, Louis Chauvet wrote:
> Planes can have name, create a plane attribute to configure it. Currently
> plane name is mainly used in logs.
> 
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> ---
>  Documentation/ABI/testing/configfs-vkms |  6 +++++
>  Documentation/gpu/vkms.rst              |  3 ++-
>  drivers/gpu/drm/vkms/vkms_configfs.c    | 43 +++++++++++++++++++++++++++++++++
>  3 files changed, 51 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
> index 0beaa25f30ba..6fe375d1636f 100644
> --- a/Documentation/ABI/testing/configfs-vkms
> +++ b/Documentation/ABI/testing/configfs-vkms
> @@ -103,6 +103,12 @@ Description:
>          Plane type. Possible values: 0 - overlay, 1 - primary,
>          2 - cursor.
>  
> +What:		/sys/kernel/config/vkms/<device>/planes/<plane>/name
> +Date:		Nov 2025
> +Contact:	dri-devel@lists.freedesktop.org
> +Description:
> +        Name of the plane.
> +
>  What:		/sys/kernel/config/vkms/<device>/planes/<plane>/possible_crtcs
>  Date:		Nov 2025
>  Contact:	dri-devel@lists.freedesktop.org
> diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
> index 1e79e62a6bc4..79f1185d8645 100644
> --- a/Documentation/gpu/vkms.rst
> +++ b/Documentation/gpu/vkms.rst
> @@ -87,10 +87,11 @@ Start by creating one or more planes::
>  
>    sudo mkdir /config/vkms/my-vkms/planes/plane0
>  
> -Planes have 1 configurable attribute:
> +Planes have 2 configurable attributes:
>  
>  - type: Plane type: 0 overlay, 1 primary, 2 cursor (same values as those
>    exposed by the "type" property of a plane)
> +- name: Name of the plane. Allowed characters are [A-Za-z1-9_-]
>  
>  Continue by creating one or more CRTCs::
>  
> diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
> index 506666e21c91..989788042191 100644
> --- a/drivers/gpu/drm/vkms/vkms_configfs.c
> +++ b/drivers/gpu/drm/vkms/vkms_configfs.c
> @@ -324,10 +324,53 @@ static ssize_t plane_type_store(struct config_item *item, const char *page,
>  	return (ssize_t)count;
>  }
>  
> +static ssize_t plane_name_show(struct config_item *item, char *page)
> +{
> +	struct vkms_configfs_plane *plane;
> +	const char *name;
> +
> +	plane = plane_item_to_vkms_configfs_plane(item);
> +
> +	scoped_guard(mutex, &plane->dev->lock)
> +		name = vkms_config_plane_get_name(plane->config);
> +
> +	if (name)
> +		return sprintf(page, "%s\n", name);
> +	return sprintf(page, "\n");
> +}
> +
> +static ssize_t plane_name_store(struct config_item *item, const char *page,
> +				size_t count)
> +{
> +	struct vkms_configfs_plane *plane;
> +	size_t str_len;
> +
> +	plane = plane_item_to_vkms_configfs_plane(item);
> +
> +	// strspn is not lenght-protected, ensure that page is a null-terminated string.
> +	str_len = strnlen(page, count);
> +	if (str_len >= count)
> +		return -EINVAL;

I made a very quick review of v3 and I'm sending the initial issues I found, but I'd need
to do a deeper review.

This check is preventing me to set the name. For example, running:

$ echo "planename" | sudo tee /sys/kernel/config/vkms/gpu1/planes/plane0/name

Fails because str_len = 10 and count = 10. Does the same happen on your side?

Jose

> +
> +	if (strspn(page, "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_-") != count - 1)
> +		return -EINVAL;
> +
> +	scoped_guard(mutex, &plane->dev->lock) {
> +		if (plane->dev->enabled)
> +			return -EBUSY;
> +
> +		vkms_config_plane_set_name(plane->config, page);
> +	}
> +
> +	return (ssize_t)count;
> +}
> +
>  CONFIGFS_ATTR(plane_, type);
> +CONFIGFS_ATTR(plane_, name);
>  
>  static struct configfs_attribute *plane_item_attrs[] = {
>  	&plane_attr_type,
> +	&plane_attr_name,
>  	NULL,
>  };
>  
> 
> -- 
> 2.51.2
> 

Re: [PATCH v3 07/33] drm/vkms: Introduce configfs for plane name

[José Expósito]

On Mon, Dec 29, 2025 at 03:40:23PM +0100, Louis Chauvet wrote:
> 
> 
> On 12/23/25 12:14, Luca Ceresoli wrote:
> > On Mon Dec 22, 2025 at 11:11 AM CET, Louis Chauvet wrote:
> > > Planes can have name, create a plane attribute to configure it. Currently
> > > plane name is mainly used in logs.
> > > 
> > > Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> > > ---
> > >   Documentation/ABI/testing/configfs-vkms |  6 +++++
> > >   Documentation/gpu/vkms.rst              |  3 ++-
> > >   drivers/gpu/drm/vkms/vkms_configfs.c    | 43 +++++++++++++++++++++++++++++++++
> > >   3 files changed, 51 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
> > > index 0beaa25f30ba..6fe375d1636f 100644
> > > --- a/Documentation/ABI/testing/configfs-vkms
> > > +++ b/Documentation/ABI/testing/configfs-vkms
> > > @@ -103,6 +103,12 @@ Description:
> > >           Plane type. Possible values: 0 - overlay, 1 - primary,
> > >           2 - cursor.
> > > 
> > > +What:		/sys/kernel/config/vkms/<device>/planes/<plane>/name
> > > +Date:		Nov 2025
> > > +Contact:	dri-devel@lists.freedesktop.org
> > > +Description:
> > > +        Name of the plane.
> > > +
> > >   What:		/sys/kernel/config/vkms/<device>/planes/<plane>/possible_crtcs
> > >   Date:		Nov 2025
> > >   Contact:	dri-devel@lists.freedesktop.org
> > > diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
> > > index 1e79e62a6bc4..79f1185d8645 100644
> > > --- a/Documentation/gpu/vkms.rst
> > > +++ b/Documentation/gpu/vkms.rst
> > > @@ -87,10 +87,11 @@ Start by creating one or more planes::
> > > 
> > >     sudo mkdir /config/vkms/my-vkms/planes/plane0
> > > 
> > > -Planes have 1 configurable attribute:
> > > +Planes have 2 configurable attributes:
> > > 
> > >   - type: Plane type: 0 overlay, 1 primary, 2 cursor (same values as those
> > >     exposed by the "type" property of a plane)
> > > +- name: Name of the plane. Allowed characters are [A-Za-z1-9_-]
> > > 
> > >   Continue by creating one or more CRTCs::
> > > 
> > > diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
> > > index 506666e21c91..989788042191 100644
> > > --- a/drivers/gpu/drm/vkms/vkms_configfs.c
> > > +++ b/drivers/gpu/drm/vkms/vkms_configfs.c
> > > @@ -324,10 +324,53 @@ static ssize_t plane_type_store(struct config_item *item, const char *page,
> > >   	return (ssize_t)count;
> > >   }
> > > 
> > > +static ssize_t plane_name_show(struct config_item *item, char *page)
> > > +{
> > > +	struct vkms_configfs_plane *plane;
> > > +	const char *name;
> > > +
> > > +	plane = plane_item_to_vkms_configfs_plane(item);
> > > +
> > > +	scoped_guard(mutex, &plane->dev->lock)
> > > +		name = vkms_config_plane_get_name(plane->config);
> > 
> > vkms_config_plane_get_name() returns a pointer to the name string, not a
> > copy. Unless I'm missing something, that string might be freed before the
> > next lines, where it is used:
> > 
> > > +
> > > +	if (name)
> > > +		return sprintf(page, "%s\n", name);
> > > +	return sprintf(page, "\n");
> > 
> > So for safety the above 3 lines whould go inside the scoped_guard().
> 
> Good catch!
> 
> This also raised some questions on the whole locking synchronization between
> configfs / config / DRM core. I will work on this topic and maybe move the
> mutex / add a refcount to vkms_config.
> 
> > > +}
> > > +
> > > +static ssize_t plane_name_store(struct config_item *item, const char *page,
> > > +				size_t count)
> > > +{
> > > +	struct vkms_configfs_plane *plane;
> > > +	size_t str_len;
> > > +
> > > +	plane = plane_item_to_vkms_configfs_plane(item);
> > > +
> > > +	// strspn is not lenght-protected, ensure that page is a null-terminated string.
> > > +	str_len = strnlen(page, count);
> > > +	if (str_len >= count)
> > > +		return -EINVAL;
> > > +
> > > +	if (strspn(page, "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_-") != count - 1)
> > > +		return -EINVAL;
> > 
> > I see you effor to make this as clean as possible, thanks. Still this is a
> > tad ugly, and should be moved to some common place at some point IMO. For
> > now it's fine, but if you need to add more user-passed strings, that could
> > be the moment to move this code.
> 
> There are multiple "user strings" in this file (notably group names), but
> currently without limitation.
> 
> I can create a tiny helper and limit all user strings to a-zA-Z0-9_-
> It will technically break the ABI, but I don't think this is a big issue.
> 
> Do you or José think this is a good idea? If so I can extract the helper for
> v4 and send a separate series to do the limitation on other strings.

From the top of my head, I think that at the moment the device name is the only
user facing string that is not limted in code? It is limited by the allowed
characters in filenames. But I might be forgetting other custom strings.

Technically, it'd be an ABI break... So, while I think it shouldn't be an issue,
I'd prefer to avoid breaking the ABI, but I leave the decision to you.

Jose
 
> > Luca
> > 
> > --
> > Luca Ceresoli, Bootlin
> > Embedded Linux and Kernel engineering
> > https://bootlin.com
> 

Re: [PATCH v3 18/33] drm/vkms: Introduce configfs for plane format

[José Expósito]

On Mon, Dec 22, 2025 at 11:11:20AM +0100, Louis Chauvet wrote:
> To allow the userspace to test many hardware configuration, introduce a
> new interface to configure the available formats per planes. VKMS supports
> multiple formats, so the userspace can choose any combination.
> 
> The supported formats are configured by writing the fourcc code in
> supported_formats:
>  # enable AR24 format
>   echo '+AR24' > /config/vkms/DEVICE_1/planes/PLANE_1/supported_formats
>  # disable AR24 format
>   echo '-AR24' > /config/vkms/DEVICE_1/planes/PLANE_1/supported_formats
>  # enable all format supported by VKMS
>   echo '+*' > /config/vkms/DEVICE_1/planes/PLANE_1/supported_formats
>  # disable all formats
>   echo '-*' > /config/vkms/DEVICE_1/planes/PLANE_1/supported_formats
> 
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> ---
>  Documentation/ABI/testing/configfs-vkms         |   9 ++
>  Documentation/gpu/vkms.rst                      |   7 +-
>  drivers/gpu/drm/vkms/tests/Makefile             |   3 +-
>  drivers/gpu/drm/vkms/tests/vkms_configfs_test.c | 102 ++++++++++++++++++++
>  drivers/gpu/drm/vkms/vkms_configfs.c            | 118 ++++++++++++++++++++++++
>  drivers/gpu/drm/vkms/vkms_configfs.h            |   6 ++
>  6 files changed, 243 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
> index 2ace79ce848a..48f92538c602 100644
> --- a/Documentation/ABI/testing/configfs-vkms
> +++ b/Documentation/ABI/testing/configfs-vkms
> @@ -153,6 +153,15 @@ Description:
>          Default color range presented to userspace, same
>          values as supported_color_ranges.
>  
> +What:		/sys/kernel/config/vkms/<device>/planes/<plane>/supported_formats
> +Date:		Nov 2025
> +Contact:	dri-devel@lists.freedesktop.org
> +Description:
> +        List of supported formats for this plane. To add a new
> +        item, write its fourcc code prefixed with '+'. To remove,
> +        use '-' prefix. Use '+*' to add all formats, '-*' to
> +        remove all.
> +
>  What:		/sys/kernel/config/vkms/<device>/planes/<plane>/possible_crtcs
>  Date:		Nov 2025
>  Contact:	dri-devel@lists.freedesktop.org
> diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
> index ab0eb2f97fc2..15d62ad963c9 100644
> --- a/Documentation/gpu/vkms.rst
> +++ b/Documentation/gpu/vkms.rst
> @@ -87,7 +87,7 @@ Start by creating one or more planes::
>  
>    sudo mkdir /config/vkms/my-vkms/planes/plane0
>  
> -Planes have 8 configurable attributes:
> +Planes have 9 configurable attributes:
>  
>  - type: Plane type: 0 overlay, 1 primary, 2 cursor (same values as those
>    exposed by the "type" property of a plane)
> @@ -109,6 +109,11 @@ Planes have 8 configurable attributes:
>    must be set too.
>  - default_color_range: Default color range presented to the userspace, same
>    values as supported_color_ranges
> +- supported_formats: List of supported formats for this plane. To add a new item in the
> +  list, write it using a plus and fourcc code: +XR24
> +  To remove a format, use a minus and its fourcc: -XR24
> +  To add all formats use +*
> +  To remove all formats, use -*
>  
>  Continue by creating one or more CRTCs::
>  
> diff --git a/drivers/gpu/drm/vkms/tests/Makefile b/drivers/gpu/drm/vkms/tests/Makefile
> index d4d9ba8d4c54..92cfa7262ba4 100644
> --- a/drivers/gpu/drm/vkms/tests/Makefile
> +++ b/drivers/gpu/drm/vkms/tests/Makefile
> @@ -3,6 +3,7 @@
>  vkms-kunit-tests-y := \
>  	vkms_config_test.o \
>  	vkms_format_test.o \
> -	vkms_color_test.o
> +	vkms_color_test.o \
> +	vkms_configfs_test.o \
>  
>  obj-$(CONFIG_DRM_VKMS_KUNIT_TEST) += vkms-kunit-tests.o
> diff --git a/drivers/gpu/drm/vkms/tests/vkms_configfs_test.c b/drivers/gpu/drm/vkms/tests/vkms_configfs_test.c
> new file mode 100644
> index 000000000000..8d02c2c459d9
> --- /dev/null
> +++ b/drivers/gpu/drm/vkms/tests/vkms_configfs_test.c
> @@ -0,0 +1,102 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +
> +#include "linux/printk.h"
> +#include <kunit/test.h>
> +
> +#include "../vkms_configfs.h"
> +
> +MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING");
> +
> +/**
> + * struct vkms_configfs_parse_format_case - Store test case for format parsing
> + * @str: Contains the string to parse
> + * @str_len: str len
> + * @expected_len: expected len of the matched format
> + * @expected_offset: expected offset in the string for the parsed format
> + */
> +struct vkms_configfs_parse_format_case {
> +	const char *str;
> +	int str_len;
> +	int expected_len;
> +	int expected_offset;
> +};
> +
> +struct vkms_configfs_parse_format_case vkms_configfs_parse_format_test_cases[] = {
> +	{
> +		.str = "+RG24",
> +		.str_len = 6,
> +		.expected_len = 5,
> +		.expected_offset = 0,
> +	}, {
> +		.str = "-RG24",
> +		.str_len = 6,
> +		.expected_len = 5,
> +		.expected_offset = 0
> +	}, {
> +		.str = "  -RG24",
> +		.str_len = 8,
> +		.expected_len = 5,
> +		.expected_offset = 2
> +	}, {
> +		.str = "+*",
> +		.str_len = 3,
> +		.expected_len = 2,
> +		.expected_offset = 0
> +	}, {
> +		.str = "-RG24+RG24",
> +		.str_len = 11,
> +		.expected_len = 5,
> +		.expected_offset = 0
> +	}, {
> +		.str = "-R1+RG24",
> +		.str_len = 9,
> +		.expected_len = 3,
> +		.expected_offset = 0
> +	}, {
> +		.str = "\n-R1",
> +		.str_len = 5,
> +		.expected_len = 3,
> +		.expected_offset = 1
> +	}, {
> +		.str = "-R1111",
> +		.str_len = 3,
> +		.expected_len = 3,
> +		.expected_offset = 0
> +	}
> +};
> +
> +static void vkms_configfs_test_parse_format(struct kunit *test)
> +{
> +	const struct vkms_configfs_parse_format_case *param = test->param_value;
> +	char *out;
> +	int len = vkms_configfs_parse_next_format(param->str, param->str + param->str_len, &out);
> +
> +	KUNIT_EXPECT_EQ(test, len, param->expected_len);
> +	KUNIT_EXPECT_PTR_EQ(test, out, param->str + param->expected_offset);
> +}
> +
> +static void vkms_configfs_test_parse_format_get_desc(struct vkms_configfs_parse_format_case *t,
> +						     char *desc)
> +{
> +	snprintf(desc, KUNIT_PARAM_DESC_SIZE, "%s", t->str);
> +}
> +
> +KUNIT_ARRAY_PARAM(vkms_configfs_test_parse_format, vkms_configfs_parse_format_test_cases,
> +		  vkms_configfs_test_parse_format_get_desc
> +);
> +
> +static struct kunit_case vkms_configfs_test_cases[] = {
> +	KUNIT_CASE_PARAM(vkms_configfs_test_parse_format,
> +			 vkms_configfs_test_parse_format_gen_params),
> +	{}
> +};
> +
> +static struct kunit_suite vkms_configfs_test_suite = {
> +	.name = "vkms-configfs",
> +	.test_cases = vkms_configfs_test_cases,
> +};
> +
> +kunit_test_suite(vkms_configfs_test_suite);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Kunit test for vkms configfs utility");
> diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
> index 7be6d10b2b68..a451d1122acf 100644
> --- a/drivers/gpu/drm/vkms/vkms_configfs.c
> +++ b/drivers/gpu/drm/vkms/vkms_configfs.c
> @@ -3,6 +3,8 @@
>  #include <linux/configfs.h>
>  #include <linux/mutex.h>
>  #include <linux/slab.h>
> +#include <linux/string.h>
> +#include <kunit/visibility.h>
>  
>  #include "vkms_drv.h"
>  #include "vkms_config.h"
> @@ -628,6 +630,120 @@ static ssize_t plane_default_color_encoding_store(struct config_item *item,
>  	return count;
>  }
>  
> +static ssize_t plane_supported_formats_show(struct config_item *item, char *page)
> +{
> +	struct vkms_configfs_plane *plane;
> +
> +	plane = plane_item_to_vkms_configfs_plane(item);
> +
> +	page[0] = '\0';
> +
> +	scoped_guard(mutex, &plane->dev->lock) {
> +		u32 *formats = vkms_config_plane_get_supported_formats(plane->config);
> +
> +		for (int i = 0;
> +		     i < vkms_config_plane_get_supported_formats_count(plane->config);
> +		     i++) {
> +			char tmp[6] = { 0 };
> +			const ssize_t ret = snprintf(tmp, ARRAY_SIZE(tmp), "%.*s\n",
> +					       (int)sizeof(*formats),
> +					       (char *)&formats[i]);
> +			if (ret < 0)
> +				return ret;
> +			/*
> +			 * Limitation of ConfigFS attributes, an attribute can't be bigger
> +			 * than PAGE_SIZE. This will crop the result if this plane support
> +			 * more than ≈1000 formats.
> +			 */
> +			if (ret + strlen(page) > PAGE_SIZE - 1)
> +				return -ENOMEM;
> +			strncat(page, tmp, ARRAY_SIZE(tmp));
> +		}
> +	}
> +
> +	return strlen(page);
> +}
> +
> +/**
> + * parse_next_format() - Parse the next format in page, skipping all non fourcc-related characters
> + * @page: page to search into
> + * @page_end: last character of the page
> + * @out: Output pointer, will point inside page
> + *
> + * Returns: size of the matched format, @out will point to the + or -
> + */
> +VISIBLE_IF_KUNIT
> +int vkms_configfs_parse_next_format(const char *page, const char *page_end, char **out)
> +{
> +	int count = page - page_end;

Shouldn't this be "page_end - page"? An example logging the variables shows
that "count" takes negative numbers:

$ echo "-XB48" | sudo tee /sys/kernel/config/vkms/gpu1/planes/plane0/supported_formats

[22854.585268] page = 000000001ec38388
[22854.585277] page_end = 000000000b71ccb5
[22854.585279] count = -6
[22854.585281] page = 00000000625917b4
[22854.585282] page_end = 000000000b71ccb5
[22854.585283] count = -1

Jose

> +	char *tmp_plus = strnchr(page, count, '+');
> +	char *tmp_minus = strnchr(page, count, '-');
> +
> +	if (!tmp_plus && !tmp_minus)
> +		return 0;
> +	if (!tmp_plus)
> +		*out = tmp_minus;
> +	else if (!tmp_minus)
> +		*out = tmp_plus;
> +	else
> +		*out = min(tmp_plus, tmp_minus);
> +
> +	char *end = *out + 1;
> +
> +	while (end < page_end) {
> +		if (!isalnum(*end) && *end != '*')
> +			break;
> +		end++;
> +	}
> +
> +	return end - *out;
> +}
> +EXPORT_SYMBOL_IF_KUNIT(vkms_configfs_parse_next_format);
> +
> +static ssize_t plane_supported_formats_store(struct config_item *item,
> +					     const char *page, size_t count)
> +{
> +	struct vkms_configfs_plane *plane;
> +
> +	plane = plane_item_to_vkms_configfs_plane(item);
> +	int ret = 0;
> +	const char *end_page = page + count;
> +
> +	scoped_guard(mutex, &plane->dev->lock) {
> +		while (1) {
> +			char *tmp;
> +			char fmt[4] = {' ', ' ', ' ', ' '};
> +			int len = vkms_configfs_parse_next_format(page, end_page, &tmp);
> +
> +			// No fourcc code found
> +			if (len <= 1 || len > 5)
> +				break;
> +
> +			page = tmp + len;
> +			memcpy(fmt, &tmp[1], min(len - 1, 4));
> +			if (tmp[0] == '+') {
> +				if (fmt[0] == '*') {
> +					ret = vkms_config_plane_add_all_formats(plane->config);
> +					if (ret)
> +						return ret;
> +				} else {
> +					ret = vkms_config_plane_add_format(plane->config,
> +									   *(int *)fmt);
> +					if (ret)
> +						return ret;
> +				}
> +			} else if (tmp[0] == '-') {
> +				if (fmt[0] == '*')
> +					vkms_config_plane_remove_all_formats(plane->config);
> +				else
> +					vkms_config_plane_remove_format(plane->config, *(int *)fmt);
> +			}
> +		}
> +	}
> +
> +	return count;
> +}
> +
>  CONFIGFS_ATTR(plane_, type);
>  CONFIGFS_ATTR(plane_, name);
>  CONFIGFS_ATTR(plane_, supported_rotations);
> @@ -636,6 +752,7 @@ CONFIGFS_ATTR(plane_, supported_color_ranges);
>  CONFIGFS_ATTR(plane_, default_color_range);
>  CONFIGFS_ATTR(plane_, supported_color_encodings);
>  CONFIGFS_ATTR(plane_, default_color_encoding);
> +CONFIGFS_ATTR(plane_, supported_formats);
>  
>  static struct configfs_attribute *plane_item_attrs[] = {
>  	&plane_attr_type,
> @@ -646,6 +763,7 @@ static struct configfs_attribute *plane_item_attrs[] = {
>  	&plane_attr_default_color_range,
>  	&plane_attr_supported_color_encodings,
>  	&plane_attr_default_color_encoding,
> +	&plane_attr_supported_formats,
>  	NULL,
>  };
>  
> diff --git a/drivers/gpu/drm/vkms/vkms_configfs.h b/drivers/gpu/drm/vkms/vkms_configfs.h
> index e9020b0043db..2774655bfcc5 100644
> --- a/drivers/gpu/drm/vkms/vkms_configfs.h
> +++ b/drivers/gpu/drm/vkms/vkms_configfs.h
> @@ -2,7 +2,13 @@
>  #ifndef _VKMS_CONFIGFS_H_
>  #define _VKMS_CONFIGFS_H_
>  
> +#include <linux/types.h>
> +
>  int vkms_configfs_register(void);
>  void vkms_configfs_unregister(void);
>  
> +#if IS_ENABLED(CONFIG_KUNIT)
> +int vkms_configfs_parse_next_format(const char *page, const char *end_page, char **out);
> +#endif
> +
>  #endif /* _VKMS_CONFIGFS_H_ */
> 
> -- 
> 2.51.2
> 

Re: [PATCH v3 18/33] drm/vkms: Introduce configfs for plane format

[José Expósito]

On Mon, Dec 22, 2025 at 11:11:20AM +0100, Louis Chauvet wrote:
> To allow the userspace to test many hardware configuration, introduce a
> new interface to configure the available formats per planes. VKMS supports
> multiple formats, so the userspace can choose any combination.
> 
> The supported formats are configured by writing the fourcc code in
> supported_formats:
>  # enable AR24 format
>   echo '+AR24' > /config/vkms/DEVICE_1/planes/PLANE_1/supported_formats
>  # disable AR24 format
>   echo '-AR24' > /config/vkms/DEVICE_1/planes/PLANE_1/supported_formats
>  # enable all format supported by VKMS
>   echo '+*' > /config/vkms/DEVICE_1/planes/PLANE_1/supported_formats
>  # disable all formats
>   echo '-*' > /config/vkms/DEVICE_1/planes/PLANE_1/supported_formats
> 
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> ---
>  Documentation/ABI/testing/configfs-vkms         |   9 ++
>  Documentation/gpu/vkms.rst                      |   7 +-
>  drivers/gpu/drm/vkms/tests/Makefile             |   3 +-
>  drivers/gpu/drm/vkms/tests/vkms_configfs_test.c | 102 ++++++++++++++++++++
>  drivers/gpu/drm/vkms/vkms_configfs.c            | 118 ++++++++++++++++++++++++
>  drivers/gpu/drm/vkms/vkms_configfs.h            |   6 ++
>  6 files changed, 243 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
> index 2ace79ce848a..48f92538c602 100644
> --- a/Documentation/ABI/testing/configfs-vkms
> +++ b/Documentation/ABI/testing/configfs-vkms
> @@ -153,6 +153,15 @@ Description:
>          Default color range presented to userspace, same
>          values as supported_color_ranges.
>  
> +What:		/sys/kernel/config/vkms/<device>/planes/<plane>/supported_formats
> +Date:		Nov 2025
> +Contact:	dri-devel@lists.freedesktop.org
> +Description:
> +        List of supported formats for this plane. To add a new
> +        item, write its fourcc code prefixed with '+'. To remove,
> +        use '-' prefix. Use '+*' to add all formats, '-*' to
> +        remove all.
> +
>  What:		/sys/kernel/config/vkms/<device>/planes/<plane>/possible_crtcs
>  Date:		Nov 2025
>  Contact:	dri-devel@lists.freedesktop.org
> diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
> index ab0eb2f97fc2..15d62ad963c9 100644
> --- a/Documentation/gpu/vkms.rst
> +++ b/Documentation/gpu/vkms.rst
> @@ -87,7 +87,7 @@ Start by creating one or more planes::
>  
>    sudo mkdir /config/vkms/my-vkms/planes/plane0
>  
> -Planes have 8 configurable attributes:
> +Planes have 9 configurable attributes:
>  
>  - type: Plane type: 0 overlay, 1 primary, 2 cursor (same values as those
>    exposed by the "type" property of a plane)
> @@ -109,6 +109,11 @@ Planes have 8 configurable attributes:
>    must be set too.
>  - default_color_range: Default color range presented to the userspace, same
>    values as supported_color_ranges
> +- supported_formats: List of supported formats for this plane. To add a new item in the
> +  list, write it using a plus and fourcc code: +XR24
> +  To remove a format, use a minus and its fourcc: -XR24
> +  To add all formats use +*
> +  To remove all formats, use -*
>  
>  Continue by creating one or more CRTCs::
>  
> diff --git a/drivers/gpu/drm/vkms/tests/Makefile b/drivers/gpu/drm/vkms/tests/Makefile
> index d4d9ba8d4c54..92cfa7262ba4 100644
> --- a/drivers/gpu/drm/vkms/tests/Makefile
> +++ b/drivers/gpu/drm/vkms/tests/Makefile
> @@ -3,6 +3,7 @@
>  vkms-kunit-tests-y := \
>  	vkms_config_test.o \
>  	vkms_format_test.o \
> -	vkms_color_test.o
> +	vkms_color_test.o \
> +	vkms_configfs_test.o \
>  
>  obj-$(CONFIG_DRM_VKMS_KUNIT_TEST) += vkms-kunit-tests.o
> diff --git a/drivers/gpu/drm/vkms/tests/vkms_configfs_test.c b/drivers/gpu/drm/vkms/tests/vkms_configfs_test.c
> new file mode 100644
> index 000000000000..8d02c2c459d9
> --- /dev/null
> +++ b/drivers/gpu/drm/vkms/tests/vkms_configfs_test.c
> @@ -0,0 +1,102 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +
> +#include "linux/printk.h"
> +#include <kunit/test.h>
> +
> +#include "../vkms_configfs.h"
> +
> +MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING");
> +
> +/**
> + * struct vkms_configfs_parse_format_case - Store test case for format parsing
> + * @str: Contains the string to parse
> + * @str_len: str len
> + * @expected_len: expected len of the matched format
> + * @expected_offset: expected offset in the string for the parsed format
> + */
> +struct vkms_configfs_parse_format_case {
> +	const char *str;
> +	int str_len;
> +	int expected_len;
> +	int expected_offset;
> +};
> +
> +struct vkms_configfs_parse_format_case vkms_configfs_parse_format_test_cases[] = {
> +	{
> +		.str = "+RG24",
> +		.str_len = 6,
> +		.expected_len = 5,
> +		.expected_offset = 0,
> +	}, {
> +		.str = "-RG24",
> +		.str_len = 6,
> +		.expected_len = 5,
> +		.expected_offset = 0
> +	}, {
> +		.str = "  -RG24",
> +		.str_len = 8,
> +		.expected_len = 5,
> +		.expected_offset = 2
> +	}, {
> +		.str = "+*",
> +		.str_len = 3,
> +		.expected_len = 2,
> +		.expected_offset = 0
> +	}, {
> +		.str = "-RG24+RG24",
> +		.str_len = 11,
> +		.expected_len = 5,
> +		.expected_offset = 0
> +	}, {
> +		.str = "-R1+RG24",
> +		.str_len = 9,
> +		.expected_len = 3,
> +		.expected_offset = 0
> +	}, {
> +		.str = "\n-R1",
> +		.str_len = 5,
> +		.expected_len = 3,
> +		.expected_offset = 1
> +	}, {
> +		.str = "-R1111",
> +		.str_len = 3,
> +		.expected_len = 3,
> +		.expected_offset = 0
> +	}
> +};
> +
> +static void vkms_configfs_test_parse_format(struct kunit *test)
> +{
> +	const struct vkms_configfs_parse_format_case *param = test->param_value;
> +	char *out;
> +	int len = vkms_configfs_parse_next_format(param->str, param->str + param->str_len, &out);
> +
> +	KUNIT_EXPECT_EQ(test, len, param->expected_len);
> +	KUNIT_EXPECT_PTR_EQ(test, out, param->str + param->expected_offset);
> +}
> +
> +static void vkms_configfs_test_parse_format_get_desc(struct vkms_configfs_parse_format_case *t,
> +						     char *desc)
> +{
> +	snprintf(desc, KUNIT_PARAM_DESC_SIZE, "%s", t->str);
> +}
> +
> +KUNIT_ARRAY_PARAM(vkms_configfs_test_parse_format, vkms_configfs_parse_format_test_cases,
> +		  vkms_configfs_test_parse_format_get_desc
> +);
> +
> +static struct kunit_case vkms_configfs_test_cases[] = {
> +	KUNIT_CASE_PARAM(vkms_configfs_test_parse_format,
> +			 vkms_configfs_test_parse_format_gen_params),
> +	{}
> +};
> +
> +static struct kunit_suite vkms_configfs_test_suite = {
> +	.name = "vkms-configfs",
> +	.test_cases = vkms_configfs_test_cases,
> +};
> +
> +kunit_test_suite(vkms_configfs_test_suite);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Kunit test for vkms configfs utility");
> diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
> index 7be6d10b2b68..a451d1122acf 100644
> --- a/drivers/gpu/drm/vkms/vkms_configfs.c
> +++ b/drivers/gpu/drm/vkms/vkms_configfs.c
> @@ -3,6 +3,8 @@
>  #include <linux/configfs.h>
>  #include <linux/mutex.h>
>  #include <linux/slab.h>
> +#include <linux/string.h>
> +#include <kunit/visibility.h>
>  
>  #include "vkms_drv.h"
>  #include "vkms_config.h"
> @@ -628,6 +630,120 @@ static ssize_t plane_default_color_encoding_store(struct config_item *item,
>  	return count;
>  }
>  
> +static ssize_t plane_supported_formats_show(struct config_item *item, char *page)
> +{
> +	struct vkms_configfs_plane *plane;
> +
> +	plane = plane_item_to_vkms_configfs_plane(item);
> +
> +	page[0] = '\0';
> +
> +	scoped_guard(mutex, &plane->dev->lock) {
> +		u32 *formats = vkms_config_plane_get_supported_formats(plane->config);
> +
> +		for (int i = 0;
> +		     i < vkms_config_plane_get_supported_formats_count(plane->config);
> +		     i++) {
> +			char tmp[6] = { 0 };
> +			const ssize_t ret = snprintf(tmp, ARRAY_SIZE(tmp), "%.*s\n",
> +					       (int)sizeof(*formats),
> +					       (char *)&formats[i]);
> +			if (ret < 0)
> +				return ret;
> +			/*
> +			 * Limitation of ConfigFS attributes, an attribute can't be bigger
> +			 * than PAGE_SIZE. This will crop the result if this plane support
> +			 * more than ≈1000 formats.
> +			 */
> +			if (ret + strlen(page) > PAGE_SIZE - 1)
> +				return -ENOMEM;
> +			strncat(page, tmp, ARRAY_SIZE(tmp));
> +		}
> +	}
> +
> +	return strlen(page);
> +}
> +
> +/**
> + * parse_next_format() - Parse the next format in page, skipping all non fourcc-related characters
> + * @page: page to search into
> + * @page_end: last character of the page
> + * @out: Output pointer, will point inside page
> + *
> + * Returns: size of the matched format, @out will point to the + or -
> + */
> +VISIBLE_IF_KUNIT
> +int vkms_configfs_parse_next_format(const char *page, const char *page_end, char **out)
> +{
> +	int count = page - page_end;
> +	char *tmp_plus = strnchr(page, count, '+');
> +	char *tmp_minus = strnchr(page, count, '-');
> +
> +	if (!tmp_plus && !tmp_minus)
> +		return 0;
> +	if (!tmp_plus)
> +		*out = tmp_minus;
> +	else if (!tmp_minus)
> +		*out = tmp_plus;
> +	else
> +		*out = min(tmp_plus, tmp_minus);
> +
> +	char *end = *out + 1;
> +
> +	while (end < page_end) {
> +		if (!isalnum(*end) && *end != '*')
> +			break;
> +		end++;
> +	}
> +
> +	return end - *out;
> +}
> +EXPORT_SYMBOL_IF_KUNIT(vkms_configfs_parse_next_format);
> +
> +static ssize_t plane_supported_formats_store(struct config_item *item,
> +					     const char *page, size_t count)
> +{
> +	struct vkms_configfs_plane *plane;
> +
> +	plane = plane_item_to_vkms_configfs_plane(item);
> +	int ret = 0;
> +	const char *end_page = page + count;
> +
> +	scoped_guard(mutex, &plane->dev->lock) {
> +		while (1) {
> +			char *tmp;
> +			char fmt[4] = {' ', ' ', ' ', ' '};
> +			int len = vkms_configfs_parse_next_format(page, end_page, &tmp);
> +
> +			// No fourcc code found
> +			if (len <= 1 || len > 5)
> +				break;
> +
> +			page = tmp + len;
> +			memcpy(fmt, &tmp[1], min(len - 1, 4));
> +			if (tmp[0] == '+') {
> +				if (fmt[0] == '*') {
> +					ret = vkms_config_plane_add_all_formats(plane->config);
> +					if (ret)
> +						return ret;
> +				} else {
> +					ret = vkms_config_plane_add_format(plane->config,
> +									   *(int *)fmt);

I have been thinking for a while about this *(int *) casting and I'm not sure if it
would work in all cases.

I had a minor concern about int vs u32 and, while I don't think int will cause
issues, u32 looks like a better type.

My main concern was about endianess. The fourcc_code() macro shifts bits around,
which takes into account endianess. My brain hurt after trying to visualize this,
so I wrote a simple tests that works on x86_64 but fails on Power PC:

static void vkms_config_test_plane_add_format(struct kunit *test)
{
	struct vkms_config *config;
	struct vkms_config_plane *plane_cfg;
	int ret;
	u32 *formats;

	config = vkms_config_default_create(false, false, false, false);
	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, config);

	plane_cfg = get_first_plane(config);

	// DRM_FORMAT_XBGR16161616 = 942948952
	char fmt[4] = {'X', 'B', '4', '8'};

	vkms_config_plane_remove_all_formats(plane_cfg);
	ret = vkms_config_plane_get_supported_formats_count(plane_cfg);
	KUNIT_EXPECT_EQ(test, ret, 0);
	
	ret = vkms_config_plane_add_format(plane_cfg, *(int *)fmt);
	KUNIT_EXPECT_EQ(test, ret, 0);

	ret = vkms_config_plane_get_supported_formats_count(plane_cfg);
	KUNIT_EXPECT_EQ(test, ret, 1);

	formats = vkms_config_plane_get_supported_formats(plane_cfg);
	KUNIT_EXPECT_EQ(test, formats[0], DRM_FORMAT_XBGR16161616);
}

On big endian it fails with the following error:

[17:55:07] # vkms_config_test_plane_add_format: EXPECTATION FAILED at drivers/gpu/drm/vkms/tests/vkms_config_test.c:1256
[17:55:07] Expected ret == 0, but
[17:55:07]     ret == -22 (0xffffffffffffffea)
[17:55:07] # vkms_config_test_plane_add_format: EXPECTATION FAILED at drivers/gpu/drm/vkms/tests/vkms_config_test.c:1259
[17:55:07] Expected ret == 1, but
[17:55:07]     ret == 0 (0x0)
[17:55:07] # vkms_config_test_plane_add_format: EXPECTATION FAILED at drivers/gpu/drm/vkms/tests/vkms_config_test.c:1262
[17:55:07] Expected formats[0] == ((__u32)('X') | ((__u32)('B') << 8) | ((__u32)('4') << 16) | ((__u32)('8') << 24)), but
[17:55:07]     formats[0] == 875713089 (0x34325241)
[17:55:07]     ((__u32)('X') | ((__u32)('B') << 8) | ((__u32)('4') << 16) | ((__u32)('8') << 24)) == 942948952 (0x38344258)
[17:55:07] [FAILED] vkms_config_test_plane_add_format
[17:55:07]     # module: vkms_kunit_tests

So we need to find another way to convert the format. Maybe using the fourcc_code() macro?

Jose

> +					if (ret)
> +						return ret;
> +				}
> +			} else if (tmp[0] == '-') {
> +				if (fmt[0] == '*')
> +					vkms_config_plane_remove_all_formats(plane->config);
> +				else
> +					vkms_config_plane_remove_format(plane->config, *(int *)fmt);
> +			}
> +		}
> +	}
> +
> +	return count;
> +}
> +
>  CONFIGFS_ATTR(plane_, type);
>  CONFIGFS_ATTR(plane_, name);
>  CONFIGFS_ATTR(plane_, supported_rotations);
> @@ -636,6 +752,7 @@ CONFIGFS_ATTR(plane_, supported_color_ranges);
>  CONFIGFS_ATTR(plane_, default_color_range);
>  CONFIGFS_ATTR(plane_, supported_color_encodings);
>  CONFIGFS_ATTR(plane_, default_color_encoding);
> +CONFIGFS_ATTR(plane_, supported_formats);
>  
>  static struct configfs_attribute *plane_item_attrs[] = {
>  	&plane_attr_type,
> @@ -646,6 +763,7 @@ static struct configfs_attribute *plane_item_attrs[] = {
>  	&plane_attr_default_color_range,
>  	&plane_attr_supported_color_encodings,
>  	&plane_attr_default_color_encoding,
> +	&plane_attr_supported_formats,
>  	NULL,
>  };
>  
> diff --git a/drivers/gpu/drm/vkms/vkms_configfs.h b/drivers/gpu/drm/vkms/vkms_configfs.h
> index e9020b0043db..2774655bfcc5 100644
> --- a/drivers/gpu/drm/vkms/vkms_configfs.h
> +++ b/drivers/gpu/drm/vkms/vkms_configfs.h
> @@ -2,7 +2,13 @@
>  #ifndef _VKMS_CONFIGFS_H_
>  #define _VKMS_CONFIGFS_H_
>  
> +#include <linux/types.h>
> +
>  int vkms_configfs_register(void);
>  void vkms_configfs_unregister(void);
>  
> +#if IS_ENABLED(CONFIG_KUNIT)
> +int vkms_configfs_parse_next_format(const char *page, const char *end_page, char **out);
> +#endif
> +
>  #endif /* _VKMS_CONFIGFS_H_ */
> 
> -- 
> 2.51.2
> 

Re: [PATCH v3 32/33] drm/vkms: Allow to hot-add connectors

[José Expósito]

On Mon, Dec 22, 2025 at 11:11:34AM +0100, Louis Chauvet wrote:
> In order to allow creating dynamic connector, add the required
> infrastructure in vkms_connector.
> 
> [Louis Chauvet: use drm_atomic_helper_connector_reset instead of
> drm_mode_config_reset because connector is not yet registered]
> 
> Co-developed-by: José Expósito <jose.exposito89@gmail.com>
> Signed-off-by: José Expósito <jose.exposito89@gmail.com>
> Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> ---
>  drivers/gpu/drm/vkms/vkms_connector.c | 81 +++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/vkms/vkms_connector.h | 33 ++++++++++++++
>  drivers/gpu/drm/vkms/vkms_output.c    |  9 ++++
>  3 files changed, 123 insertions(+)
> 
> diff --git a/drivers/gpu/drm/vkms/vkms_connector.c b/drivers/gpu/drm/vkms/vkms_connector.c
> index 3ad614642355..616036494937 100644
> --- a/drivers/gpu/drm/vkms/vkms_connector.c
> +++ b/drivers/gpu/drm/vkms/vkms_connector.c
> @@ -163,9 +163,90 @@ struct vkms_connector *vkms_connector_init_static(struct vkms_device *vkmsdev,
>  	return connector;
>  }
>  
> +static void vkms_connector_dynamic_destroy(struct drm_connector *connector)
> +{
> +	struct drm_device *dev = connector->dev;
> +	struct vkms_connector *vkms_connector;
> +
> +	drm_connector_cleanup(connector);
> +
> +	vkms_connector = drm_connector_to_vkms_connector(connector);
> +	drmm_kfree(dev, vkms_connector);
> +}
> +
> +static const struct drm_connector_funcs vkms_dynamic_connector_funcs = {
> +	.fill_modes = drm_helper_probe_single_connector_modes,
> +	.reset = drm_atomic_helper_connector_reset,
> +	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
> +	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> +	.destroy = vkms_connector_dynamic_destroy,
> +	.detect = vkms_connector_detect,
> +};
> +
>  void vkms_trigger_connector_hotplug(struct vkms_device *vkmsdev)
>  {
>  	struct drm_device *dev = &vkmsdev->drm;
>  
>  	drm_kms_helper_hotplug_event(dev);
>  }
> +
> +struct vkms_connector *vkms_connector_hot_add(struct vkms_device *vkmsdev,
> +					      struct vkms_config_connector *connector_cfg)
> +{
> +	struct vkms_config_encoder *encoder_cfg;
> +	struct vkms_connector *connector;
> +	int ret;
> +	unsigned long idx = 0;
> +
> +	connector = drmm_kzalloc(&vkmsdev->drm, sizeof(*connector), GFP_KERNEL);
> +	if (IS_ERR(connector))

I need to test this patch carefully, but in a first review I noticed that this
"if" should check for NULL, not for error.

Jose

> +		return connector;
> +	ret = drm_connector_dynamic_init(&vkmsdev->drm,
> +					 &connector->base,
> +					 &vkms_dynamic_connector_funcs,
> +					 connector_cfg->type,
> +					 NULL);
> +	if (ret)
> +		return ERR_PTR(ret);
> +	drm_connector_helper_add(&connector->base, &vkms_conn_helper_funcs);
> +
> +	vkms_config_connector_for_each_possible_encoder(connector_cfg, idx, encoder_cfg) {
> +		ret = drm_connector_attach_encoder(&connector->base,
> +						   encoder_cfg->encoder);
> +		if (ret)
> +			return ERR_PTR(ret);
> +	}
> +
> +	drm_atomic_helper_connector_reset(&connector->base);
> +
> +	vkms_connector_init(vkmsdev, connector, connector_cfg);
> +
> +	ret = drm_connector_dynamic_register(&connector->base);
> +	if (ret)
> +		return ERR_PTR(ret);
> +
> +	return connector;
> +}
> +
> +void vkms_connector_hot_remove(struct vkms_device *vkmsdev,
> +			       struct vkms_connector *connector)
> +{
> +	drm_connector_unregister(&connector->base);
> +	drm_mode_config_reset(&vkmsdev->drm);
> +	drm_connector_put(&connector->base);
> +}
> +
> +int vkms_connector_hot_attach_encoder(struct vkms_device *vkmsdev,
> +				      struct vkms_connector *connector,
> +				      struct drm_encoder *encoder)
> +{
> +	int ret;
> +
> +	ret = drm_connector_attach_encoder(&connector->base, encoder);
> +	if (ret)
> +		return ret;
> +
> +	drm_mode_config_reset(&vkmsdev->drm);
> +
> +	return ret;
> +}
> diff --git a/drivers/gpu/drm/vkms/vkms_connector.h b/drivers/gpu/drm/vkms/vkms_connector.h
> index 85f9082c710e..a235a518d5a0 100644
> --- a/drivers/gpu/drm/vkms/vkms_connector.h
> +++ b/drivers/gpu/drm/vkms/vkms_connector.h
> @@ -34,4 +34,37 @@ struct vkms_connector *vkms_connector_init_static(struct vkms_device *vkmsdev,
>   */
>  void vkms_trigger_connector_hotplug(struct vkms_device *vkmsdev);
>  
> +/**
> + * vkms_connector_hot_add() - Create a connector after the device is created
> + * @vkmsdev: Device to hot-add the connector to
> + * @connector_cfg: Connector's configuration
> + *
> + * Returns:
> + * A pointer to the newly created connector or a PTR_ERR on failure.
> + */
> +struct vkms_connector *vkms_connector_hot_add(struct vkms_device *vkmsdev,
> +					      struct vkms_config_connector *connector_cfg);
> +
> +/**
> + * vkms_connector_hot_remove() - Remove a connector after a device is created
> + * @vkmsdev: Device to containing the connector to be removed
> + * @connector: The connector to hot-remove
> + */
> +void vkms_connector_hot_remove(struct vkms_device *vkmsdev,
> +			       struct vkms_connector *connector);
> +
> +/**
> + * vkms_connector_hot_attach_encoder() - Attach a connector to a encoder after
> + * the device is created.
> + * @vkmsdev: Device containing the connector and the encoder
> + * @connector: Connector to attach to @encoder
> + * @encoder: Target encoder
> + *
> + * Returns:
> + * 0 on success or an error on failure.
> + */
> +int vkms_connector_hot_attach_encoder(struct vkms_device *vkmsdev,
> +				      struct vkms_connector *connector,
> +				      struct drm_encoder *encoder);
> +
>  #endif /* _VKMS_CONNECTOR_H_ */
> diff --git a/drivers/gpu/drm/vkms/vkms_output.c b/drivers/gpu/drm/vkms/vkms_output.c
> index 13c4ca5fd39d..50f7d88dee8b 100644
> --- a/drivers/gpu/drm/vkms/vkms_output.c
> +++ b/drivers/gpu/drm/vkms/vkms_output.c
> @@ -117,5 +117,14 @@ int vkms_output_init(struct vkms_device *vkmsdev)
>  
>  	drm_mode_config_reset(dev);
>  
> +	vkms_config_for_each_connector_dynamic(vkmsdev->config, connector_cfg) {
> +		if (connector_cfg->enabled) {
> +			connector_cfg->connector = vkms_connector_hot_add(vkmsdev, connector_cfg);
> +
> +			if (IS_ERR(connector_cfg->connector))
> +				return PTR_ERR(connector_cfg->connector);
> +		}
> +	}
> +
>  	return 0;
>  }
> 
> -- 
> 2.51.2
> 

Re: [PATCH v3 33/33] drm/vkms: Introduce configfs for dynamic connector creation

[José Expósito]

On Mon, Dec 22, 2025 at 11:11:35AM +0100, Louis Chauvet wrote:
> DRM allows the connector to be created after the device. To allows
> emulating this, add two configfs attributes to connector to allows this.
> 
> Using the dynamic attribute you can set if a connector will be dynamic or
> not.
> Using the enabled attribute, you can set at runtime if a dynamic connector
> is present or not.
> 
> Co-developed-by: José Expósito <jose.exposito89@gmail.com>
> Signed-off-by: José Expósito <jose.exposito89@gmail.com>
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> ---
>  Documentation/ABI/testing/configfs-vkms |  14 +++
>  Documentation/gpu/vkms.rst              |   6 +-
>  drivers/gpu/drm/vkms/vkms_configfs.c    | 146 ++++++++++++++++++++++++++++++--
>  3 files changed, 155 insertions(+), 11 deletions(-)
> 
> diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
> index 4061ada5d88b..a7fce35fcf91 100644
> --- a/Documentation/ABI/testing/configfs-vkms
> +++ b/Documentation/ABI/testing/configfs-vkms
> @@ -62,6 +62,20 @@ Description:
>          Content of the EDID for this connector. Ignored if
>          edid_enabled is not set.
>  
> +What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/dynamic
> +Date:		Nov 2025
> +Contact:	dri-devel@lists.freedesktop.org
> +Description:
> +        Set to 1 to create a dynamic connector (emulates DP MST).
> +        Value: 1 - dynamic, 0 - static.
> +
> +What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/enabled
> +Date:		Nov 2025
> +Contact:	dri-devel@lists.freedesktop.org
> +Description:
> +        For dynamic connectors, set to 1 to create the connector,
> +        0 to remove it. Value: 1 - enabled, 0 - disabled.
> +
>  What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/possible_encoders
>  Date:		Nov 2025
>  Contact:	dri-devel@lists.freedesktop.org
> diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
> index 60367fd1bd65..fce229fbfc7c 100644
> --- a/Documentation/gpu/vkms.rst
> +++ b/Documentation/gpu/vkms.rst
> @@ -138,7 +138,7 @@ Last but not least, create one or more connectors::
>  
>    sudo mkdir /config/vkms/my-vkms/connectors/connector0
>  
> -Connectors have 5 configurable attribute:
> +Connectors have 7 configurable attribute:
>  
>  - status: Connection status: 1 connected, 2 disconnected, 3 unknown (same values
>    as those exposed by the "status" property of a connector)
> @@ -150,7 +150,9 @@ Connectors have 5 configurable attribute:
>  - edid_enabled: Enable or not EDID for this connector. Some connectors may not have an
>    EDID but just a list of modes, this attribute allows to disable EDID property.
>  - edid: Content of the EDID. Ignored if edid_enabled is not set
> -
> +- dynamic: Set to 1 while configuring the device to create a dynamic connector. A dynamic
> +  connector can be used to emulate DP MST connectors.
> +- enabled: For dynamic connector, set it to 1 to create the connector, 0 to remove it.
>  
>  To finish the configuration, link the different pipeline items::
>  
> diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
> index 20f5150e8b24..657381a8a4c2 100644
> --- a/drivers/gpu/drm/vkms/vkms_configfs.c
> +++ b/drivers/gpu/drm/vkms/vkms_configfs.c
> @@ -1144,6 +1144,12 @@ static ssize_t connector_status_show(struct config_item *item, char *page)
>  	return sprintf(page, "%u", status);
>  }
>  
> +static bool connector_is_enabled(struct vkms_config_connector *connector_cfg)
> +{
> +	return !connector_cfg->dynamic ||
> +	       (connector_cfg->dynamic && connector_cfg->enabled);
> +}
> +
>  static ssize_t connector_status_store(struct config_item *item,
>  				      const char *page, size_t count)
>  {
> @@ -1163,7 +1169,7 @@ static ssize_t connector_status_store(struct config_item *item,
>  	scoped_guard(mutex, &connector->dev->lock) {
>  		vkms_config_connector_set_status(connector->config, status);
>  
> -		if (connector->dev->enabled)
> +		if (connector->dev->enabled && connector_is_enabled(connector->config))
>  			vkms_trigger_connector_hotplug(connector->dev->config->dev);
>  	}
>  
> @@ -1224,7 +1230,7 @@ static ssize_t connector_type_store(struct config_item *item,
>  	}
>  
>  	scoped_guard(mutex, &connector->dev->lock) {
> -		if (connector->dev->enabled)
> +		if (connector->dev->enabled && connector_is_enabled(connector->config))
>  			return -EBUSY;
>  
>  		vkms_config_connector_set_type(connector->config, val);
> @@ -1343,6 +1349,107 @@ static ssize_t connector_edid_store(struct config_item *item,
>  		    connector_status_disconnected)
>  			vkms_trigger_connector_hotplug(connector->dev->config->dev);
>  	}
> +	return count;
> +}
> +
> +static ssize_t connector_enabled_show(struct config_item *item, char *page)
> +{
> +	struct vkms_configfs_connector *connector;
> +	bool enabled;
> +
> +	connector = connector_item_to_vkms_configfs_connector(item);
> +
> +	scoped_guard(mutex, &connector->dev->lock)
> +		enabled = vkms_config_connector_is_enabled(connector->config);
> +
> +	return sprintf(page, "%d\n", enabled);
> +}
> +
> +static ssize_t connector_enabled_store(struct config_item *item,
> +				       const char *page, size_t count)
> +{
> +	struct vkms_configfs_connector *connector;
> +	struct vkms_config_connector *connector_cfg;
> +	bool enabled, was_enabled;
> +
> +	connector = connector_item_to_vkms_configfs_connector(item);
> +	connector_cfg = connector->config;
> +
> +	if (kstrtobool(page, &enabled))
> +		return -EINVAL;
> +	scoped_guard(mutex, &connector->dev->lock) {
> +		if (!connector->dev->enabled) {
> +			vkms_config_connector_set_enabled(connector_cfg, enabled);
> +		} else {
> +			// Only dynamic connector can be enabled/disabled at runtime
> +			if (!connector_cfg->dynamic)
> +				return -EBUSY;
> +
> +			was_enabled = vkms_config_connector_is_enabled(connector_cfg);
> +			vkms_config_connector_set_enabled(connector_cfg, enabled);
> +
> +			// Resulting configuration is invalid (missing encoder for example)
> +			// Early return to avoid drm core issue
> +			if (!vkms_config_is_valid(connector->dev->config)) {
> +				count = -EINVAL;
> +				goto rollback;

Since this rollback jumps out of the guard, there is a chance that, while the connector is
"enabled" (enabled as in the variable) and before is set to "was_enabled", another thread
is executed and reads an invalid value.

The cleanup path needs to be inside the guard.

Jose

> +			}
> +
> +			if (!was_enabled && enabled) {
> +				// Adding the connector
> +				connector_cfg->connector = vkms_connector_hot_add(connector->dev->config->dev,
> +										  connector_cfg);
> +				if (IS_ERR(connector_cfg->connector)) {
> +					count = PTR_ERR(connector_cfg->connector);
> +					goto rollback;
> +				}
> +			} else if (was_enabled && !enabled) {
> +				vkms_connector_hot_remove(connector->dev->config->dev,
> +							  connector_cfg->connector);
> +			}
> +		}
> +	}
> +	return count;
> +
> +rollback:
> +	vkms_config_connector_set_enabled(connector_cfg, was_enabled);
> +	return count;
> +}
> +
> +static ssize_t connector_dynamic_show(struct config_item *item, char *page)
> +{
> +	struct vkms_configfs_connector *connector;
> +	bool enabled;
> +
> +	connector = connector_item_to_vkms_configfs_connector(item);
> +
> +	scoped_guard(mutex, &connector->dev->lock) {
> +		enabled = vkms_config_connector_is_dynamic(connector->config);
> +	}
> +
> +	return sprintf(page, "%d\n", enabled);
> +}
> +
> +static ssize_t connector_dynamic_store(struct config_item *item,
> +				       const char *page, size_t count)
> +{
> +	struct vkms_configfs_connector *connector;
> +	struct vkms_config_connector *connector_cfg;
> +	bool dynamic;
> +
> +	connector = connector_item_to_vkms_configfs_connector(item);
> +	connector_cfg = connector->config;
> +
> +	if (kstrtobool(page, &dynamic))
> +		return -EINVAL;
> +
> +	scoped_guard(mutex, &connector->dev->lock) {
> +		// Can't change the dynamic status when the device is activated
> +		if (connector->dev->enabled)
> +			return -EBUSY;
> +
> +		vkms_config_connector_set_dynamic(connector_cfg, dynamic);
> +	}
>  
>  	return count;
>  }
> @@ -1352,6 +1459,8 @@ CONFIGFS_ATTR(connector_, type);
>  CONFIGFS_ATTR(connector_, supported_colorspaces);
>  CONFIGFS_ATTR(connector_, edid_enabled);
>  CONFIGFS_ATTR(connector_, edid);
> +CONFIGFS_ATTR(connector_, dynamic);
> +CONFIGFS_ATTR(connector_, enabled);
>  
>  static struct configfs_attribute *connector_item_attrs[] = {
>  	&connector_attr_status,
> @@ -1359,19 +1468,28 @@ static struct configfs_attribute *connector_item_attrs[] = {
>  	&connector_attr_supported_colorspaces,
>  	&connector_attr_edid_enabled,
>  	&connector_attr_edid,
> +	&connector_attr_dynamic,
> +	&connector_attr_enabled,
>  	NULL,
>  };
>  
>  static void connector_release(struct config_item *item)
>  {
>  	struct vkms_configfs_connector *connector;
> +	struct vkms_config_connector *connector_cfg;
>  	struct mutex *lock;
>  
>  	connector = connector_item_to_vkms_configfs_connector(item);
> +	connector_cfg = connector->config;
>  	lock = &connector->dev->lock;
>  
>  	scoped_guard(mutex, lock) {
> +		if (connector->dev->enabled && connector_cfg->dynamic && connector_cfg->enabled)
> +			vkms_connector_hot_remove(connector->dev->config->dev,
> +						  connector_cfg->connector);
> +
>  		vkms_config_destroy_connector(connector->config);
> +
>  		kfree(connector);
>  	}
>  }
> @@ -1390,6 +1508,7 @@ static int connector_possible_encoders_allow_link(struct config_item *src,
>  						  struct config_item *target)
>  {
>  	struct vkms_configfs_connector *connector;
> +	struct vkms_config_connector *connector_cfg;
>  	struct vkms_configfs_encoder *encoder;
>  	int ret;
>  
> @@ -1397,16 +1516,26 @@ static int connector_possible_encoders_allow_link(struct config_item *src,
>  		return -EINVAL;
>  
>  	connector = connector_possible_encoders_item_to_vkms_configfs_connector(src);
> +	connector_cfg = connector->config;
>  	encoder = encoder_item_to_vkms_configfs_encoder(target);
>  
>  	scoped_guard(mutex, &connector->dev->lock) {
> -		if (connector->dev->enabled)
> -			return -EBUSY;
> +		if (connector->dev->enabled && connector_cfg->enabled) {
> +			if (!connector_cfg->dynamic)
> +				return -EBUSY;
> +
> +			ret = vkms_connector_hot_attach_encoder(connector->dev->config->dev,
> +								connector->config->connector,
> +								encoder->config->encoder);
> +			if (ret)
> +				return ret;
> +		}
>  
>  		ret = vkms_config_connector_attach_encoder(connector->config,
>  							   encoder->config);
> +		if (ret)
> +			return ret;
>  	}
> -
>  	return ret;
>  }
>  
> @@ -1445,9 +1574,6 @@ static struct config_group *make_connector_group(struct config_group *group,
>  	dev = child_group_to_vkms_configfs_device(group);
>  
>  	scoped_guard(mutex, &dev->lock) {
> -		if (dev->enabled)
> -			return ERR_PTR(-EBUSY);
> -
>  		connector = kzalloc(sizeof(*connector), GFP_KERNEL);
>  		if (!connector)
>  			return ERR_PTR(-ENOMEM);
> @@ -1461,9 +1587,11 @@ static struct config_group *make_connector_group(struct config_group *group,
>  			return ERR_PTR(ret);
>  		}
>  
> +		vkms_config_connector_set_dynamic(connector->config, connector->dev->enabled);
> +		vkms_config_connector_set_enabled(connector->config, !connector->dev->enabled);
> +
>  		config_group_init_type_name(&connector->group, name,
>  					    &connector_item_type);
> -
>  		config_group_init_type_name(&connector->possible_encoders_group,
>  					    "possible_encoders",
>  					    &connector_possible_encoders_group_type);
> 
> -- 
> 2.51.2
> 

Re: [PATCH v3 28/33] drm/vkms: Introduce configfs for connector EDID

[José Expósito]

On Mon, Dec 22, 2025 at 11:11:30AM +0100, Louis Chauvet wrote:
> Introduce new attributes to configure EDID of a connector:
> - edid_enable - chose if the connector will have an EDID or not
> - edid - raw edid content
> 
> Due to limitation of ConfigFS, the max len of EDID is PAGE_SIZE (4kB on
> x86), it should be sufficient for many tests. One possible evolution is
> using a ConfigFS blob to allow bigger EDID.
> 
> Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> ---
>  Documentation/ABI/testing/configfs-vkms | 14 ++++++
>  Documentation/gpu/vkms.rst              |  5 ++-
>  drivers/gpu/drm/vkms/vkms_configfs.c    | 80 +++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/vkms/vkms_connector.c   |  3 ++
>  4 files changed, 101 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
> index f750e616be54..4061ada5d88b 100644
> --- a/Documentation/ABI/testing/configfs-vkms
> +++ b/Documentation/ABI/testing/configfs-vkms
> @@ -48,6 +48,20 @@ Description:
>          Value is a bitfield, where 0x1 = NO_DATA, 0x2 = SMPTE_170M_YCC,
>          etc. See enum drm_colorspace for full list.
>  
> +What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/edid_enabled
> +Date:		Nov 2025
> +Contact:	dri-devel@lists.freedesktop.org
> +Description:
> +        Enable or disable EDID for this connector. Value:
> +        1 - enabled, 0 - disabled.
> +
> +What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/edid
> +Date:		Nov 2025
> +Contact:	dri-devel@lists.freedesktop.org
> +Description:
> +        Content of the EDID for this connector. Ignored if
> +        edid_enabled is not set.
> +
>  What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/possible_encoders
>  Date:		Nov 2025
>  Contact:	dri-devel@lists.freedesktop.org
> diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
> index 1c4a8023374c..60367fd1bd65 100644
> --- a/Documentation/gpu/vkms.rst
> +++ b/Documentation/gpu/vkms.rst
> @@ -138,7 +138,7 @@ Last but not least, create one or more connectors::
>  
>    sudo mkdir /config/vkms/my-vkms/connectors/connector0
>  
> -Connectors have 3 configurable attribute:
> +Connectors have 5 configurable attribute:
>  
>  - status: Connection status: 1 connected, 2 disconnected, 3 unknown (same values
>    as those exposed by the "status" property of a connector)
> @@ -147,6 +147,9 @@ Connectors have 3 configurable attribute:
>    If supported_colorspaces is not 0, the HDR_OUTPUT_METADATA will also be created.
>    Value is a bitfield, 0x1 = NO_DATA, 0x2 = SMPTE_170M_YCC... see enum drm_colorspace
>    for full list.
> +- edid_enabled: Enable or not EDID for this connector. Some connectors may not have an
> +  EDID but just a list of modes, this attribute allows to disable EDID property.
> +- edid: Content of the EDID. Ignored if edid_enabled is not set
>  
>  
>  To finish the configuration, link the different pipeline items::
> diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
> index 90bf6e6995ae..20f5150e8b24 100644
> --- a/drivers/gpu/drm/vkms/vkms_configfs.c
> +++ b/drivers/gpu/drm/vkms/vkms_configfs.c
> @@ -1271,14 +1271,94 @@ static ssize_t connector_supported_colorspaces_store(struct config_item *item,
>  	return count;
>  }
>  
> +static ssize_t connector_edid_enabled_show(struct config_item *item, char *page)
> +{
> +	struct vkms_configfs_connector *connector;
> +	bool enabled;
> +
> +	connector = connector_item_to_vkms_configfs_connector(item);
> +
> +	scoped_guard(mutex, &connector->dev->lock)
> +		enabled = vkms_config_connector_get_edid_enabled(connector->config);
> +
> +	return sprintf(page, "%d\n", enabled);
> +}
> +
> +static ssize_t connector_edid_enabled_store(struct config_item *item,
> +					    const char *page, size_t count)
> +{
> +	struct vkms_configfs_connector *connector;
> +	struct vkms_config_connector *connector_cfg;
> +	bool enabled;
> +
> +	connector = connector_item_to_vkms_configfs_connector(item);
> +	connector_cfg = connector->config;
> +
> +	if (kstrtobool(page, &enabled))
> +		return -EINVAL;
> +
> +	scoped_guard(mutex, &connector->dev->lock)
> +	{
> +		vkms_config_connector_set_edid_enabled(connector_cfg, enabled);
> +
> +		if (connector->dev->enabled &&
> +		    vkms_config_connector_get_status(connector_cfg) !=
> +		    connector_status_disconnected)
> +			vkms_trigger_connector_hotplug(connector->dev->config->dev);
> +	}
> +	return count;
> +}
> +
> +static ssize_t connector_edid_show(struct config_item *item, char *page)
> +{
> +	struct vkms_configfs_connector *connector;
> +
> +	connector = connector_item_to_vkms_configfs_connector(item);
> +
> +	scoped_guard(mutex, &connector->dev->lock)
> +	{
> +		unsigned int len = 0;
> +		const u8 *edid = vkms_config_connector_get_edid(connector->config, &len);
> +
> +		memcpy(page, edid, min(len, PAGE_SIZE));
> +		return min(len, PAGE_SIZE);
> +	}
> +
> +	return -EINVAL;

This return is unreachable, the guard block returns unconditionally.

> +}
> +
> +static ssize_t connector_edid_store(struct config_item *item,
> +				    const char *page, size_t count)
> +{
> +	struct vkms_configfs_connector *connector;
> +
> +	connector = connector_item_to_vkms_configfs_connector(item);
> +
> +	scoped_guard(mutex, &connector->dev->lock)
> +	{
> +		vkms_config_connector_set_edid(connector->config, page, count);
> +
> +		if (connector->dev->enabled &&
> +		    vkms_config_connector_get_status(connector->config) !=
> +		    connector_status_disconnected)
> +			vkms_trigger_connector_hotplug(connector->dev->config->dev);
> +	}
> +
> +	return count;
> +}
> +
>  CONFIGFS_ATTR(connector_, status);
>  CONFIGFS_ATTR(connector_, type);
>  CONFIGFS_ATTR(connector_, supported_colorspaces);
> +CONFIGFS_ATTR(connector_, edid_enabled);
> +CONFIGFS_ATTR(connector_, edid);
>  
>  static struct configfs_attribute *connector_item_attrs[] = {
>  	&connector_attr_status,
>  	&connector_attr_type,
>  	&connector_attr_supported_colorspaces,
> +	&connector_attr_edid_enabled,
> +	&connector_attr_edid,
>  	NULL,
>  };
>  
> diff --git a/drivers/gpu/drm/vkms/vkms_connector.c b/drivers/gpu/drm/vkms/vkms_connector.c
> index c85d19013720..311858727175 100644
> --- a/drivers/gpu/drm/vkms/vkms_connector.c
> +++ b/drivers/gpu/drm/vkms/vkms_connector.c
> @@ -143,6 +143,9 @@ struct vkms_connector *vkms_connector_init(struct vkms_device *vkmsdev,
>  
>  	drm_connector_helper_add(&connector->base, &vkms_conn_helper_funcs);
>  
> +	if (vkms_config_connector_get_edid_enabled(connector_cfg))
> +		drm_connector_attach_edid_property(&connector->base);
> +
>  	return connector;
>  }
>  
> 
> -- 
> 2.51.2
> 

Re: [PATCH v3 28/33] drm/vkms: Introduce configfs for connector EDID

[José Expósito]

On Mon, Dec 22, 2025 at 11:11:30AM +0100, Louis Chauvet wrote:
> Introduce new attributes to configure EDID of a connector:
> - edid_enable - chose if the connector will have an EDID or not
> - edid - raw edid content
> 
> Due to limitation of ConfigFS, the max len of EDID is PAGE_SIZE (4kB on
> x86), it should be sufficient for many tests. One possible evolution is
> using a ConfigFS blob to allow bigger EDID.
> 
> Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> ---
>  Documentation/ABI/testing/configfs-vkms | 14 ++++++
>  Documentation/gpu/vkms.rst              |  5 ++-
>  drivers/gpu/drm/vkms/vkms_configfs.c    | 80 +++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/vkms/vkms_connector.c   |  3 ++
>  4 files changed, 101 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
> index f750e616be54..4061ada5d88b 100644
> --- a/Documentation/ABI/testing/configfs-vkms
> +++ b/Documentation/ABI/testing/configfs-vkms
> @@ -48,6 +48,20 @@ Description:
>          Value is a bitfield, where 0x1 = NO_DATA, 0x2 = SMPTE_170M_YCC,
>          etc. See enum drm_colorspace for full list.
>  
> +What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/edid_enabled
> +Date:		Nov 2025
> +Contact:	dri-devel@lists.freedesktop.org
> +Description:
> +        Enable or disable EDID for this connector. Value:
> +        1 - enabled, 0 - disabled.
> +
> +What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/edid
> +Date:		Nov 2025
> +Contact:	dri-devel@lists.freedesktop.org
> +Description:
> +        Content of the EDID for this connector. Ignored if
> +        edid_enabled is not set.
> +
>  What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/possible_encoders
>  Date:		Nov 2025
>  Contact:	dri-devel@lists.freedesktop.org
> diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
> index 1c4a8023374c..60367fd1bd65 100644
> --- a/Documentation/gpu/vkms.rst
> +++ b/Documentation/gpu/vkms.rst
> @@ -138,7 +138,7 @@ Last but not least, create one or more connectors::
>  
>    sudo mkdir /config/vkms/my-vkms/connectors/connector0
>  
> -Connectors have 3 configurable attribute:
> +Connectors have 5 configurable attribute:
>  
>  - status: Connection status: 1 connected, 2 disconnected, 3 unknown (same values
>    as those exposed by the "status" property of a connector)
> @@ -147,6 +147,9 @@ Connectors have 3 configurable attribute:
>    If supported_colorspaces is not 0, the HDR_OUTPUT_METADATA will also be created.
>    Value is a bitfield, 0x1 = NO_DATA, 0x2 = SMPTE_170M_YCC... see enum drm_colorspace
>    for full list.
> +- edid_enabled: Enable or not EDID for this connector. Some connectors may not have an
> +  EDID but just a list of modes, this attribute allows to disable EDID property.
> +- edid: Content of the EDID. Ignored if edid_enabled is not set
>  
>  
>  To finish the configuration, link the different pipeline items::
> diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
> index 90bf6e6995ae..20f5150e8b24 100644
> --- a/drivers/gpu/drm/vkms/vkms_configfs.c
> +++ b/drivers/gpu/drm/vkms/vkms_configfs.c
> @@ -1271,14 +1271,94 @@ static ssize_t connector_supported_colorspaces_store(struct config_item *item,
>  	return count;
>  }
>  
> +static ssize_t connector_edid_enabled_show(struct config_item *item, char *page)
> +{
> +	struct vkms_configfs_connector *connector;
> +	bool enabled;
> +
> +	connector = connector_item_to_vkms_configfs_connector(item);
> +
> +	scoped_guard(mutex, &connector->dev->lock)
> +		enabled = vkms_config_connector_get_edid_enabled(connector->config);
> +
> +	return sprintf(page, "%d\n", enabled);
> +}
> +
> +static ssize_t connector_edid_enabled_store(struct config_item *item,
> +					    const char *page, size_t count)
> +{
> +	struct vkms_configfs_connector *connector;
> +	struct vkms_config_connector *connector_cfg;
> +	bool enabled;
> +
> +	connector = connector_item_to_vkms_configfs_connector(item);
> +	connector_cfg = connector->config;
> +
> +	if (kstrtobool(page, &enabled))
> +		return -EINVAL;
> +
> +	scoped_guard(mutex, &connector->dev->lock)
> +	{
> +		vkms_config_connector_set_edid_enabled(connector_cfg, enabled);
> +
> +		if (connector->dev->enabled &&
> +		    vkms_config_connector_get_status(connector_cfg) !=
> +		    connector_status_disconnected)
> +			vkms_trigger_connector_hotplug(connector->dev->config->dev);
> +	}
> +	return count;
> +}
> +
> +static ssize_t connector_edid_show(struct config_item *item, char *page)
> +{
> +	struct vkms_configfs_connector *connector;
> +
> +	connector = connector_item_to_vkms_configfs_connector(item);
> +
> +	scoped_guard(mutex, &connector->dev->lock)
> +	{

Sorry for the additional email. I forgot to mention that this brace should go
in the same line.

> +		unsigned int len = 0;
> +		const u8 *edid = vkms_config_connector_get_edid(connector->config, &len);
> +
> +		memcpy(page, edid, min(len, PAGE_SIZE));
> +		return min(len, PAGE_SIZE);
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static ssize_t connector_edid_store(struct config_item *item,
> +				    const char *page, size_t count)
> +{
> +	struct vkms_configfs_connector *connector;
> +
> +	connector = connector_item_to_vkms_configfs_connector(item);
> +
> +	scoped_guard(mutex, &connector->dev->lock)
> +	{
> +		vkms_config_connector_set_edid(connector->config, page, count);
> +
> +		if (connector->dev->enabled &&
> +		    vkms_config_connector_get_status(connector->config) !=
> +		    connector_status_disconnected)
> +			vkms_trigger_connector_hotplug(connector->dev->config->dev);
> +	}
> +
> +	return count;
> +}
> +
>  CONFIGFS_ATTR(connector_, status);
>  CONFIGFS_ATTR(connector_, type);
>  CONFIGFS_ATTR(connector_, supported_colorspaces);
> +CONFIGFS_ATTR(connector_, edid_enabled);
> +CONFIGFS_ATTR(connector_, edid);
>  
>  static struct configfs_attribute *connector_item_attrs[] = {
>  	&connector_attr_status,
>  	&connector_attr_type,
>  	&connector_attr_supported_colorspaces,
> +	&connector_attr_edid_enabled,
> +	&connector_attr_edid,
>  	NULL,
>  };
>  
> diff --git a/drivers/gpu/drm/vkms/vkms_connector.c b/drivers/gpu/drm/vkms/vkms_connector.c
> index c85d19013720..311858727175 100644
> --- a/drivers/gpu/drm/vkms/vkms_connector.c
> +++ b/drivers/gpu/drm/vkms/vkms_connector.c
> @@ -143,6 +143,9 @@ struct vkms_connector *vkms_connector_init(struct vkms_device *vkmsdev,
>  
>  	drm_connector_helper_add(&connector->base, &vkms_conn_helper_funcs);
>  
> +	if (vkms_config_connector_get_edid_enabled(connector_cfg))
> +		drm_connector_attach_edid_property(&connector->base);
> +
>  	return connector;
>  }
>  
> 
> -- 
> 2.51.2
> 

Re: [PATCH v3 26/33] drm/vkms: Introduce configfs for connector supported colorspace

[José Expósito]

On Mon, Dec 22, 2025 at 11:11:28AM +0100, Louis Chauvet wrote:
> Add the attribute supported_colorspaces to configure the supported
> colorspace of a connector. It will allows emulating some HDR features of
> displays. This feature is only supported for HDMI, DP and eDP connectors.
> 
> Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
> ---
>  Documentation/ABI/testing/configfs-vkms |  8 +++++++
>  Documentation/gpu/vkms.rst              |  7 +++++-
>  drivers/gpu/drm/vkms/vkms_configfs.c    | 40 +++++++++++++++++++++++++++++++++
>  3 files changed, 54 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/ABI/testing/configfs-vkms b/Documentation/ABI/testing/configfs-vkms
> index 5452140cc508..f750e616be54 100644
> --- a/Documentation/ABI/testing/configfs-vkms
> +++ b/Documentation/ABI/testing/configfs-vkms
> @@ -40,6 +40,14 @@ Description:
>          Type of the connector. Possible values match those
>          exposed by the "type" field in drm_connector.
>  
> +What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/supported_colorspaces
> +Date:		Nov 2025
> +Contact:	dri-devel@lists.freedesktop.org
> +Description:
> +        Supported colorspaces for HDMI, DP, and eDP connectors.
> +        Value is a bitfield, where 0x1 = NO_DATA, 0x2 = SMPTE_170M_YCC,
> +        etc. See enum drm_colorspace for full list.
> +
>  What:		/sys/kernel/config/vkms/<device>/connectors/<connector>/possible_encoders
>  Date:		Nov 2025
>  Contact:	dri-devel@lists.freedesktop.org
> diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
> index 41c6f4733663..1c4a8023374c 100644
> --- a/Documentation/gpu/vkms.rst
> +++ b/Documentation/gpu/vkms.rst
> @@ -138,11 +138,16 @@ Last but not least, create one or more connectors::
>  
>    sudo mkdir /config/vkms/my-vkms/connectors/connector0
>  
> -Connectors have 2 configurable attribute:
> +Connectors have 3 configurable attribute:
>  
>  - status: Connection status: 1 connected, 2 disconnected, 3 unknown (same values
>    as those exposed by the "status" property of a connector)
>  - type: Type of connector. Same values as exposed by the "type" field in drm_connector.
> +- supported_colorspaces: Supported colorspaces values for HDMI, DP and eDP connectors.
> +  If supported_colorspaces is not 0, the HDR_OUTPUT_METADATA will also be created.
> +  Value is a bitfield, 0x1 = NO_DATA, 0x2 = SMPTE_170M_YCC... see enum drm_colorspace
> +  for full list.
> +
>  
>  To finish the configuration, link the different pipeline items::
>  
> diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c
> index d6a85d6c466f..90bf6e6995ae 100644
> --- a/drivers/gpu/drm/vkms/vkms_configfs.c
> +++ b/drivers/gpu/drm/vkms/vkms_configfs.c
> @@ -1233,12 +1233,52 @@ static ssize_t connector_type_store(struct config_item *item,
>  	return count;
>  }
>  
> +static ssize_t connector_supported_colorspaces_show(struct config_item *item, char *page)
> +{
> +	struct vkms_configfs_connector *connector;
> +	int colorspaces;
> +
> +	connector = connector_item_to_vkms_configfs_connector(item);
> +
> +	scoped_guard(mutex, &connector->dev->lock)
> +	colorspaces = vkms_config_connector_get_supported_colorspaces(connector->config);

Missing identation in this line.

> +
> +	return sprintf(page, "%u", colorspaces);
> +}
> +
> +static ssize_t connector_supported_colorspaces_store(struct config_item *item,
> +						     const char *page, size_t count)
> +{
> +	struct vkms_configfs_connector *connector;
> +	int val, ret;
> +
> +	connector = connector_item_to_vkms_configfs_connector(item);
> +
> +	ret = kstrtouint(page, 10, &val);
> +	if (ret)
> +		return ret;
> +
> +	if ((val & -BIT(DRM_MODE_COLORIMETRY_COUNT)) != 0)
> +		return -EINVAL;
> +
> +	scoped_guard(mutex, &connector->dev->lock) {
> +		if (connector->dev->enabled)
> +			return -EBUSY;
> +
> +		vkms_config_connector_set_supported_colorspaces(connector->config, val);
> +	}
> +
> +	return count;
> +}
> +
>  CONFIGFS_ATTR(connector_, status);
>  CONFIGFS_ATTR(connector_, type);
> +CONFIGFS_ATTR(connector_, supported_colorspaces);
>  
>  static struct configfs_attribute *connector_item_attrs[] = {
>  	&connector_attr_status,
>  	&connector_attr_type,
> +	&connector_attr_supported_colorspaces,
>  	NULL,
>  };
>  
> 
> -- 
> 2.51.2
> 

Re: [PATCH v3 18/33] drm/vkms: Introduce configfs for plane format

[Bagas Sanjaya]

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On Mon, Dec 29, 2025 at 04:33:47PM +0100, Louis Chauvet wrote:
> > @@ -202,7 +202,7 @@ Contact:	dri-devel@lists.freedesktop.org
> >   Description:
> >           List of supported formats for this plane. To add a new
> >           item, write its fourcc code prefixed with '+'. To remove,
> > -        use '-' prefix. Use '+*' to add all formats, '-*' to
> > +        use '-' prefix. Use '+*' to add all formats, '-\*' to
> 
> Hi, thanks for the fix!
> 
> I only have to escape the second wildcard? Not the `+*`?

Yup. Try make htmldocs without the patch and see.

-- 
An old man doll... just what I always wanted! - Clara

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Re: [PATCH v3 17/33] drm/vkms: Introduce config for plane format

[Luca Ceresoli]

Hi Louis,

On Mon Dec 29, 2025 at 4:29 PM CET, Louis Chauvet wrote:
>>> --- a/drivers/gpu/drm/vkms/vkms_config.c
>>> +++ b/drivers/gpu/drm/vkms/vkms_config.c
>>
>>> +void vkms_config_plane_remove_all_formats(struct vkms_config_plane *plane_cfg)
>>> +{
>>> +	plane_cfg->supported_formats_count = 0;
>>
>> Why not kfree(plane_cfg->supported_formats) too? You will be (re)allocating
>> anyway if adding one or all formats later on, so the buffer you're not
>> freeing won't be reused anyway.
>
> IIRC realloc reuse the existing allocated buffer if it is big enough to fit the new
> size. But I think this is probably an oversight here and I will add the free to clarify the situation :-)

Thanks. My point is that keeping the buffer allocated for future use is not
great because if it is not reused it will take memory for all the remaining
uptime.

>>> +}
>>> +
>>> +void vkms_config_plane_remove_format(struct vkms_config_plane *plane_cfg, u32 drm_format)
>>> +{
>>> +	for (unsigned int i = 0; i < plane_cfg->supported_formats_count; i++) {
>>> +		if (plane_cfg->supported_formats[i] == drm_format) {
>>> +			plane_cfg->supported_formats[i] = plane_cfg->supported_formats[plane_cfg->supported_formats_count - 1];
>>
>> I doubt these are less than 100 chars. ;-)
>
> yes, 127, but I don't know how to format it so it is readable.
>
> I tried
>
> plane_cfg->supported_formats[i] =
> 	plane_cfg->supported_formats[plane_cfg->supported_formats_count - 1];
>
> But the second line is 101 chars...

I vote for this one. 101 is close enough to 100, and I see no reaonable way
to format better (and I agree the two below are ugly).

> Checkpatch don't complain if I do:
>
> plane_cfg->supported_formats[i] =
> 	plane_cfg->supported_formats[
> 		plane_cfg->supported_formats_count - 1];
>
> or
>
> plane_cfg->supported_formats[i] =
> 	plane_cfg->supported_formats[plane_cfg->supported_formats_count-
> 		1];
>
> But that very ugly and not readable...

Luca

--
Luca Ceresoli, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com