Commit 8f86c82a authored by Simon Ser's avatar Simon Ser
Browse files

drm/connector: demote connector force-probes for non-master clients 



Force-probing a connector can be slow and cause flickering. As this
affects the global KMS state, let's make it so only the DRM master
can force-probe a connector.

Non-master DRM clients won't be able to force-probe a connector
anymore. Instead, KMS will perform a regular read-only connector
query.

Signed-off-by: default avatarSimon Ser <contact@emersion.fr>
Acked-by: default avatarPekka Paalanen <pekka.paalanen@collabora.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210402112212.5625-1-contact@emersion.fr
parent 4aae79f7

drivers/gpu/drm/drm_connector.c

+8 −3
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 
 * OF THIS SOFTWARE.

 */



#include <drm/drm_auth.h>

#include <drm/drm_connector.h>

#include <drm/drm_edid.h>

#include <drm/drm_encoder.h>
@@ -2376,9 +2377,13 @@ int drm_mode_getconnector(struct drm_device *dev, void *data, 


	mutex_lock(&dev->mode_config.mutex);

	if (out_resp->count_modes == 0) {

		if (drm_is_current_master(file_priv))

			connector->funcs->fill_modes(connector,

						     dev->mode_config.max_width,

						     dev->mode_config.max_height);

		else

			drm_dbg_kms(dev, "User-space requested a forced probe on [CONNECTOR:%d:%s] but is not the DRM master, demoting to read-only probe",

				    connector->base.id, connector->name);

	}



	out_resp->mm_width = connector->display_info.width_mm;

include/uapi/drm/drm_mode.h

+4 −3
Original line number Diff line number Diff line
@@ -413,9 +413,10 @@ enum drm_mode_subconnector { 
 *

 * **Force-probing a connector**

 *

 * If the @count_modes field is set to zero, the kernel will perform a forced

 * probe on the connector to refresh the connector status, modes and EDID.

 * A forced-probe can be slow, might cause flickering and the ioctl will block.

 * If the @count_modes field is set to zero and the DRM client is the current

 * DRM master, the kernel will perform a forced probe on the connector to

 * refresh the connector status, modes and EDID. A forced-probe can be slow,

 * might cause flickering and the ioctl will block.

 *

 * User-space needs to force-probe connectors to ensure their metadata is

 * up-to-date at startup and after receiving a hot-plug event. User-space