Commit d67b6a20 authored by Liviu Dudau's avatar Liviu Dudau
Browse files

drm: writeback: Add client capability for exposing writeback connectors 



Due to the fact that writeback connectors behave in a special way
in DRM (they always report being disconnected) we might confuse some
userspace. Add a client capability for writeback connectors that will
filter them out for clients that don't understand the capability.

Changelog:
 - only accept the capability if the client has already set the
DRM_CLIENT_CAP_ATOMIC one.

Cc: Sean Paul <seanpaul@chromium.org>
Cc: Brian Starkey <brian.starkey@arm.com>
Signed-off-by: default avatarLiviu Dudau <liviu.dudau@arm.com>
Reviewed-by: default avatarEric Anholt <eric@anholt.net>
Reviewed-by: default avatarBrian Starkey <brian.starkey@arm.com>
Link: https://patchwork.freedesktop.org/patch/229038/
parent b13cc8dd

drivers/gpu/drm/drm_ioctl.c

+7 −0
Original line number Diff line number Diff line
@@ -334,6 +334,13 @@ drm_setclientcap(struct drm_device *dev, void *data, struct drm_file *file_priv) 
			return -EINVAL;

		file_priv->aspect_ratio_allowed = req->value;

		break;

	case DRM_CLIENT_CAP_WRITEBACK_CONNECTORS:

		if (!file_priv->atomic)

			return -EINVAL;

		if (req->value > 1)

			return -EINVAL;

		file_priv->writeback_connectors = req->value;

		break;

	default:

		return -EINVAL;

	}

drivers/gpu/drm/drm_mode_config.c

+5 −0
Original line number Diff line number Diff line
@@ -145,6 +145,11 @@ int drm_mode_getresources(struct drm_device *dev, void *data, 
	count = 0;

	connector_id = u64_to_user_ptr(card_res->connector_id_ptr);

	drm_for_each_connector_iter(connector, &conn_iter) {

		/* only expose writeback connectors if userspace understands them */

		if (!file_priv->writeback_connectors &&

		    (connector->connector_type == DRM_MODE_CONNECTOR_WRITEBACK))

			continue;



		if (drm_lease_held(file_priv, connector->base.id)) {

			if (count < card_res->count_connectors &&

			    put_user(connector->base.id, connector_id + count)) {

include/drm/drm_file.h

+7 −0
Original line number Diff line number Diff line
@@ -192,6 +192,13 @@ struct drm_file { 
	 */

	unsigned aspect_ratio_allowed:1;



	/**

	 * @writeback_connectors:

	 *

	 * True if client understands writeback connectors

	 */

	unsigned writeback_connectors:1;



	/**

	 * @is_master:

	 *

include/uapi/drm/drm.h

+9 −0
Original line number Diff line number Diff line
@@ -687,6 +687,15 @@ struct drm_get_cap { 
 */

#define DRM_CLIENT_CAP_ASPECT_RATIO    4



/**

 * DRM_CLIENT_CAP_WRITEBACK_CONNECTORS

 *

 * If set to 1, the DRM core will expose special connectors to be used for

 * writing back to memory the scene setup in the commit. Depends on client

 * also supporting DRM_CLIENT_CAP_ATOMIC

 */

#define DRM_CLIENT_CAP_WRITEBACK_CONNECTORS	5



/** DRM_IOCTL_SET_CLIENT_CAP ioctl argument type */

struct drm_set_client_cap {

	__u64 capability;

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