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

["José Expósito" <jose.exposito89@gmail.com>]

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
>