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.
Re-requested-by: Sean Paul seanpaul@chromium.org Cc: Brian Starkey brian.starkey@arm.com Signed-off-by: Liviu Dudau liviu.dudau@arm.com --- drivers/gpu/drm/drm_ioctl.c | 5 +++++ drivers/gpu/drm/drm_mode_config.c | 5 +++++ include/drm/drm_file.h | 7 +++++++ include/uapi/drm/drm.h | 9 +++++++++ 4 files changed, 26 insertions(+)
diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c index 02ffa0e8d77b..48895a469963 100644 --- a/drivers/gpu/drm/drm_ioctl.c +++ b/drivers/gpu/drm/drm_ioctl.c @@ -322,6 +322,11 @@ drm_setclientcap(struct drm_device *dev, void *data, struct drm_file *file_priv) file_priv->atomic = req->value; file_priv->universal_planes = req->value; break; + case DRM_CLIENT_CAP_WRITEBACK_CONNECTORS: + if (!file_priv->atomic || !drm_core_check_feature(dev, DRIVER_ATOMIC)) + return -EINVAL; + file_priv->writeback_connectors = req->value; + break; default: return -EINVAL; } diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c index e5c653357024..21e353bd3948 100644 --- a/drivers/gpu/drm/drm_mode_config.c +++ b/drivers/gpu/drm/drm_mode_config.c @@ -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)) { diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h index 5176c3797680..2a09b3c8965c 100644 --- a/include/drm/drm_file.h +++ b/include/drm/drm_file.h @@ -181,6 +181,13 @@ struct drm_file { /** @atomic: True if client understands atomic properties. */ unsigned atomic:1;
+ /** + * @writeback_connectors: + * + * True if client understands writeback connectors + */ + unsigned writeback_connectors:1; + /** * @is_master: * diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h index 6fdff5945c8a..59f27ea928b4 100644 --- a/include/uapi/drm/drm.h +++ b/include/uapi/drm/drm.h @@ -680,6 +680,15 @@ struct drm_get_cap { */ #define DRM_CLIENT_CAP_ATOMIC 3
+/** + * 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 4 + /** DRM_IOCTL_SET_CLIENT_CAP ioctl argument type */ struct drm_set_client_cap { __u64 capability;