[PATCH v4 32/37] drm/vkms: Introduce configfs for connector EDID

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

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 1b80ad111a04..8215cd3ff466 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 a6215bbe1c52..a7d6a4a3b53b 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 5994b9a999b1..cf388851910b 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -1274,14 +1274,94 @@ 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 fe42ab2ba7b1..f726c7995524 100644
--- a/drivers/gpu/drm/vkms/vkms_connector.c
+++ b/drivers/gpu/drm/vkms/vkms_connector.c
@@ -175,6 +175,9 @@ struct vkms_connector *vkms_connector_init_static(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;
 }
 

-- 
2.54.0