[PATCH v4 30/37] drm/vkms: Introduce configfs for connector supported colorspace

[Louis Chauvet <louis.chauvet@bootlin.com>]

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 7f0dd0789f0a..1b80ad111a04 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 db86a956e137..a6215bbe1c52 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 a0b3347b2bd8..5994b9a999b1 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -1236,12 +1236,52 @@ 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,
 };
 

-- 
2.54.0