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 /include/drm | |
| parent | drm: Move timestamping constants into drm_vblank_crtc (diff) | |
| download | linux-dev-3bb403bf421b5b00366a9041a7edc0a1f6494f5e.tar.xz linux-dev-3bb403bf421b5b00366a9041a7edc0a1f6494f5e.zip | |
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 'include/drm')
| -rw-r--r-- | include/drm/drmP.h | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/include/drm/drmP.h b/include/drm/drmP.h index 299886746c82..b2a95e7cfeee 100644 --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -482,6 +482,7 @@ struct drm_driver { * scanout position query. Can be NULL to skip timestamp. * \param *etime Target location for timestamp taken immediately after * scanout position query. Can be NULL to skip timestamp. + * \param mode Current display timings. * * Returns vpos as a positive number while in active scanout area. * Returns vpos as a negative number inside vblank, counting the number @@ -499,8 +500,9 @@ struct drm_driver { */ int (*get_scanout_position) (struct drm_device *dev, int crtc, unsigned int flags, - int *vpos, int *hpos, ktime_t *stime, - ktime_t *etime); + int *vpos, int *hpos, + ktime_t *stime, ktime_t *etime, + const struct drm_display_mode *mode); /** * Called by \c drm_get_last_vbltimestamp. Should return a precise |