[PATCH RESEND v2 27/32] drm/vkms: Introduce configfs for connector EDID

Louis Chauvet posted 32 patches 3 months, 1 week ago
There is a newer version of this series
[PATCH RESEND v2 27/32] drm/vkms: Introduce configfs for connector EDID
Posted by Louis Chauvet 3 months, 1 week ago
Introduce new attributes to configure EDID of a connector:
- edid_enable - chose if the connector will have an EDD 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.

Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 Documentation/gpu/vkms.rst            |  5 ++-
 drivers/gpu/drm/vkms/vkms_configfs.c  | 80 +++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_connector.c |  3 ++
 3 files changed, 87 insertions(+), 1 deletion(-)

diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
index c762cadac6f4..0cc7897d7b83 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 a7f4589403ce..1843e5d9e1e1 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -1260,14 +1260,94 @@ 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 339d747e729e..699b6779a46c 100644
--- a/drivers/gpu/drm/vkms/vkms_connector.c
+++ b/drivers/gpu/drm/vkms/vkms_connector.c
@@ -141,6 +141,9 @@ 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;
 }
 

-- 
2.51.0
Re: [PATCH RESEND v2 27/32] drm/vkms: Introduce configfs for connector EDID
Posted by Luca Ceresoli 1 month, 3 weeks ago
On Wed Oct 29, 2025 at 3:37 PM CET, Louis Chauvet wrote:
> Introduce new attributes to configure EDID of a connector:
> - edid_enable - chose if the connector will have an EDD or not
                                                      EDID

> - 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.
>
> Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>

With that fixed:

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


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