diff options
| author | Ville Syrjälä | 2018-11-22 16:34:11 +0200 |
|---|---|---|
| committer | Ville Syrjälä | 2018-11-23 14:45:34 +0200 |
| commit | 2de42f79bb21a412f40ade8831eb6fc445cb78a4 (patch) | |
| tree | 4aae8a7aa505df473c327e0576ed3b8b8abd849d | |
| parent | 10fdb7d2ad4244c668f33706f98d019795fc63c8 (diff) | |
drm/atomic-helper: Complete fake_commit->flip_done potentially earlier
Consider the following scenario:
1. nonblocking enable crtc
2. wait for the event
3. nonblocking disable crtc
On i915 this can lead to a spurious -EBUSY from step 3 on
account of non-enabled planes getting the fake_commit in step 1
and we don't complete the fake_commit-> flip_done until
drm_atomic_helper_commit_hw_done() which can happen a long
time after the flip event was sent out.
This will become somewhat easy to hit on SKL+ once we start
to add all the planes for the crtc to every modeset commit
for the purposes of forcing a watermark register programming
[1].
To make the race a little less pronounced let's complete
fake_commit->flip_done after drm_atomic_helper_wait_for_flip_done().
For the single crtc case this should make the race quite
theoretical, assuming drm_atomic_helper_wait_for_flip_done()
actually has to wait for the real commit flip_done. In case
the real commit flip_done gets completed singificantly before
drm_atomic_helper_wait_for_flip_done(), or we are dealing with
multiple crtcs whose vblanks don't line up nicely the race still
exists.
[1] https://patchwork.freedesktop.org/patch/262670/
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Fixes: 080de2e5be2d ("drm/atomic: Check for busy planes/connectors before setting the commit")
Testcase: igt/kms_cursor_legacy/*nonblocking-modeset-vs-cursor-atomic
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181122143412.11655-1-ville.syrjala@linux.intel.com
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
| -rw-r--r-- | drivers/gpu/drm/drm_atomic_helper.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 474b503a73a1..269f1a74de38 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -1456,6 +1456,9 @@ void drm_atomic_helper_wait_for_flip_done(struct drm_device *dev, DRM_ERROR("[CRTC:%d:%s] flip_done timed out\n", crtc->base.id, crtc->name); } + + if (old_state->fake_commit) + complete_all(&old_state->fake_commit->flip_done); } EXPORT_SYMBOL(drm_atomic_helper_wait_for_flip_done); |