From 777974bc2b043c5f8952834ecdc8ea63987ffd41 Mon Sep 17 00:00:00 2001 From: Mario Kleiner Date: Mon, 24 Apr 2017 18:54:20 +0200 Subject: [PATCH 0334/4131] drm/amd/display: Prevent premature pageflip when comitting in vblank. (v3) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Acked-by: Harry Wentland (v1) Reviewed-by: Michel Dänzer Reviewed-by: Andrey Grodzovsky Cc: Harry Wentland Cc: Alex Deucher Cc: Michel Dänzer Signed-off-by: Alex Deucher --- .../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 f0896e8..fa8769b 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 @@ -2487,6 +2487,9 @@ 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 @@ -2505,13 +2508,9 @@ 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, @@ -2787,14 +2786,15 @@ 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