diff options
| author | Ville Syrjälä <ville.syrjala@linux.intel.com> | 2015-09-14 22:43:44 +0300 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2015-09-24 20:14:21 +0200 |
| commit | 3bb403bf421b5b00366a9041a7edc0a1f6494f5e (patch) | |
| tree | d280555ef17c89c2a1e952d03749d230547598c3 /drivers/gpu/drm/drm_irq.c | |
| parent | eba1f35dfe145247c7eb690c7c32740fde8ec699 (diff) | |
drm: Stop using linedur_ns and pixeldur_ns for vblank timestamps
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>
Diffstat (limited to 'drivers/gpu/drm/drm_irq.c')
| -rw-r--r-- | drivers/gpu/drm/drm_irq.c | 19 |
1 files changed, 8 insertions, 11 deletions
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 6b2fefde25a8..9fab3334eb6b 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -694,12 +694,11 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, unsigned flags, const struct drm_display_mode *mode) { - struct drm_vblank_crtc *vblank = &dev->vblank[pipe]; struct timeval tv_etime; ktime_t stime, etime; int vbl_status; int vpos, hpos, i; - int framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns; + int delta_ns, duration_ns; bool invbl; if (pipe >= dev->num_crtcs) { @@ -713,15 +712,10 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, return -EIO; } - /* Durations of frames, lines, pixels in nanoseconds. */ - framedur_ns = vblank->framedur_ns; - linedur_ns = vblank->linedur_ns; - pixeldur_ns = vblank->pixeldur_ns; - /* If mode timing undefined, just return as no-op: * Happens during initial modesetting of a crtc. */ - if (framedur_ns == 0) { + if (mode->crtc_clock == 0) { DRM_DEBUG("crtc %u: Noop due to uninitialized mode.\n", pipe); return -EAGAIN; } @@ -738,8 +732,10 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, * Get vertical and horizontal scanout position vpos, hpos, * and bounding timestamps stime, etime, pre/post query. */ - vbl_status = dev->driver->get_scanout_position(dev, pipe, flags, &vpos, - &hpos, &stime, &etime); + vbl_status = dev->driver->get_scanout_position(dev, pipe, flags, + &vpos, &hpos, + &stime, &etime, + mode); /* Return as no-op if scanout query unsupported or failed. */ if (!(vbl_status & DRM_SCANOUTPOS_VALID)) { @@ -776,7 +772,8 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, * since start of scanout at first display scanline. delta_ns * can be negative if start of scanout hasn't happened yet. */ - delta_ns = vpos * linedur_ns + hpos * pixeldur_ns; + delta_ns = div_s64(1000000LL * (vpos * mode->crtc_htotal + hpos), + mode->crtc_clock); if (!drm_timestamp_monotonic) etime = ktime_mono_to_real(etime); |