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: Simon Ser <contact@xxxxxxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Cc: Pekka Paalanen <ppaalanen@xxxxxxxxx>
---
drivers/gpu/drm/drm_connector.c | 11 ++++++++---
include/uapi/drm/drm_mode.h | 7 ++++---
2 files changed, 12 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 7631f76e7f34..2f70a52a892b 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -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>
@@ -2374,9 +2375,13 @@ int drm_mode_getconnector(struct drm_device *dev, void *data,
mutex_lock(&dev->mode_config.mutex);
if (out_resp->count_modes == 0) {
- connector->funcs->fill_modes(connector,
- dev->mode_config.max_width,
- dev->mode_config.max_height);
+ 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;
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index a5e76aa06ad5..3efa2e38d89b 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -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 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
--
2.31.1
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