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

José Expósito
2025-12-29T17:26:13Z

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
>