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drm: Stop using linedur_ns and pixeldur_ns for vblank timestamps

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linedur_ns, and especially pixeldur_ns are becoming rather inaccurate
to be used for the vblank timestamp correction. With 4k@60 the pixel
duration is already below 2ns, so the amount of error due to the
truncation to nanoseconds is introducing quite a bit of error.

We can avoid such problems if we instead calculate the timestamp
delta_ns directly from the dislay timings, avoiding the use of
these intermediate truncated values.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
[danvet: Squash in fixup from Thierry Reding for amdgpu.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Ville Syrjälä
2015-09-14 22:43:44 +03:00
committed by Daniel Vetter
parent eba1f35dfe
commit 3bb403bf42
11 changed files with 43 additions and 34 deletions
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4
drivers/gpu/drm/radeon/radeon_pm.c
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@@ -1733,7 +1733,9 @@ static bool radeon_pm_in_vbl(struct radeon_device *rdev)
*/
for (crtc = 0; (crtc < rdev->num_crtc) && in_vbl; crtc++) {
if (rdev->pm.active_crtcs & (1 << crtc)) {
vbl_status = radeon_get_crtc_scanoutpos(rdev->ddev, crtc, 0, &vpos, &hpos, NULL, NULL);
vbl_status = radeon_get_crtc_scanoutpos(rdev->ddev, crtc, 0,
&vpos, &hpos, NULL, NULL,
&rdev->mode_info.crtcs[crtc]->base.hwmode);
if ((vbl_status & DRM_SCANOUTPOS_VALID) &&
!(vbl_status & DRM_SCANOUTPOS_IN_VBLANK))
in_vbl = false;