Make sure we do not program a hw pageflip inside vblank 'n' iff the
atomic flip is comitted while inside the same vblank 'n'. We must
defer such a flip by one refresh cycle to vblank 'n+1', unless this
is a DRM_MODE_PAGE_FLIP_ASYNC async pageflip, which must always
execute as soon as possible.
Without this, pageflips programmed via X11 GLX_OML_sync_control extensions
glXSwapBuffersMscOML(..., target_msc, ...); call and/or via DRI3/Present
PresentPixmap(..., target_msc, ...); request will complete one vblank
too early whenever target_msc > current_msc + 1, ie. more than 1 vblank
in the future. In such a case, the call of the pageflip ioctl() would be
triggered by a queued drmWaitVblank() vblank event, which itself gets
dispatched inside the vblank one frame before the target_msc vblank.
Testing with this patch does no longer show any problems with
OML_sync_control swap scheduling or flip completion timestamps.
Tested on R9 380 Tonga.
v2: Add acked/r-b by Harry and Michel.
v3: Feedback from Andrey: Must not wait an extra frame for
DRM_MODE_PAGE_FLIP_ASYNC flips.
Signed-off-by: Mario Kleiner <mario.kleiner.de at gmail.com>
Acked-by: Harry Wentland <harry.wentland at amd.com>
Reviewed-by: Michel Dänzer <michel.daenzer at amd.com>
Cc: Harry Wentland <Harry.Wentland at amd.com>
Cc: Alex Deucher <alexander.deucher at amd.com>
Cc: Michel Dänzer <michel.daenzer at amd.com>
---
.../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_types.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_types.c
index 086a842..82b2ce6 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_types.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_types.c
@@ -2460,6 +2460,9 @@ static void amdgpu_dm_do_flip(
struct amdgpu_device *adev = crtc->dev->dev_private;
bool async_flip = (acrtc->flip_flags & DRM_MODE_PAGE_FLIP_ASYNC) != 0;
+ /* Prepare wait for target vblank early - before the fence-waits */
+ target_vblank = target - drm_crtc_vblank_count(crtc) +
+ amdgpu_get_vblank_counter_kms(crtc->dev, acrtc->crtc_id);
/*TODO This might fail and hence better not used, wait
* explicitly on fences instead
@@ -2478,13 +2481,9 @@ static void amdgpu_dm_do_flip(
amdgpu_bo_unreserve(abo);
- /* Wait for target vblank */
/* Wait until we're out of the vertical blank period before the one
* targeted by the flip
*/
- target_vblank = target - drm_crtc_vblank_count(crtc) +
- amdgpu_get_vblank_counter_kms(crtc->dev, acrtc->crtc_id);
-
while ((acrtc->enabled &&
(amdgpu_get_crtc_scanoutpos(adev->ddev, acrtc->crtc_id, 0,
&vpos, &hpos, NULL, NULL,
@@ -2760,14 +2759,15 @@ void amdgpu_dm_atomic_commit_tail(
pflip_needed = !state->allow_modeset;
if (pflip_needed) {
+ wait_for_vblank =
+ acrtc->flip_flags & DRM_MODE_PAGE_FLIP_ASYNC ?
+ false : true;
+
amdgpu_dm_do_flip(
- crtc,
- fb,
- drm_crtc_vblank_count(crtc));
+ crtc,
+ fb,
+ drm_crtc_vblank_count(crtc) + wait_for_vblank);
- wait_for_vblank =
- acrtc->flip_flags & DRM_MODE_PAGE_FLIP_ASYNC ?
- false : true;
/*clean up the flags for next usage*/
acrtc->flip_flags = 0;
}
--
2.7.4
