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@emersion.fr Cc: Daniel Vetter daniel@ffwll.ch Cc: Pekka Paalanen ppaalanen@gmail.com --- 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
On Fri, 2 Apr 2021 13:22:12 +0200 Simon Ser contact@emersion.fr wrote:
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@emersion.fr Cc: Daniel Vetter daniel@ffwll.ch Cc: Pekka Paalanen ppaalanen@gmail.com
Hi,
seems like a good idea to me. Acked-by: Pekka Paalanen pekka.paalanen@collabora.com
Btw. can force-probe be triggered via sysfs as well and does it require root privs?
Thanks, pq
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);elsedrm_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
On Wednesday, April 7th, 2021 at 9:02 AM, Pekka Paalanen ppaalanen@gmail.com wrote:
Btw. can force-probe be triggered via sysfs as well and does it require root privs?
sysfs can force-probe like so:
echo detect | sudo tee /sys/class/drm/card0-DP-1/status
But this requires root, yes.
On Wed, 07 Apr 2021 07:16:30 +0000 Simon Ser contact@emersion.fr wrote:
On Wednesday, April 7th, 2021 at 9:02 AM, Pekka Paalanen ppaalanen@gmail.com wrote:
Btw. can force-probe be triggered via sysfs as well and does it require root privs?
sysfs can force-probe like so:
echo detect | sudo tee /sys/class/drm/card0-DP-1/statusBut this requires root, yes.
Ah, all good then.
Thanks, pq
On Fri, Apr 02, 2021 at 01:22:12PM +0200, Simon Ser wrote:
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@emersion.fr Cc: Daniel Vetter daniel@ffwll.ch Cc: Pekka Paalanen ppaalanen@gmail.com
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);elsedrm_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
*current* DRM master
The drm master/client relationship survives a DROPMASTER ioctl, but also it's only really relevant for the old authmagic dance. But just to be consistent here.
- 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.
Do we have an igt for this? Timing test should do the job I think, assuming we have at least one output which requires an edid read (so maybe skip the test if a forced probe takes less than 10ms or so).
Patch lgtm, but igt would be really nice here.
Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch
- 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
On Tuesday, April 20th, 2021 at 11:14 AM, Daniel Vetter daniel@ffwll.ch wrote:
Do we have an igt for this? Timing test should do the job I think, assuming we have at least one output which requires an edid read (so maybe skip the test if a forced probe takes less than 10ms or so).
Err, an igt that only relies on timings? Sorry, but that sounds like a recipe for flaky tests.
Ideally a chamelium test would allow to make sure all of this works as expected. I don't really have this hw anymore though.
dri-devel@lists.freedesktop.org
-
Daniel Vetter -
Pekka Paalanen -
Simon Ser