diff options
| author | Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com> | 2018-02-02 21:13:01 -0800 |
|---|---|---|
| committer | Rodrigo Vivi <rodrigo.vivi@intel.com> | 2018-02-15 11:50:14 -0800 |
| commit | d0bb96b4be69feea97f16de5306c35e280658931 (patch) | |
| tree | 3c9016ad4c3087d2bba13f4c783b43b15c54eb36 /include/drm/drm_vblank.h | |
| parent | 68036b08b91bc491ccc308f902616a570a49227c (diff) | |
drm/vblank: Restoring vblank counts after device PM events.
The HW frame counter can get reset if device enters a low power state after
vblank interrupts were disabled. This messes up any following vblank count
update as a negative diff (huge unsigned diff) is calculated from the HW
frame counter change. We cannot ignore negative diffs altogther as there
could be legitimate wrap arounds. So, allow drivers to update vblank->count
with missed vblanks for the time interrupts were disabled. This is similar
to _crtc_vblank_on() except that vblanks interrupts are not enabled at the
end as this function is expected to be called from the driver
_enable_vblank() vfunc.
v2: drm_crtc_vblank_restore should take crtc as arg. (Chris)
Add docs and sprinkle some asserts.
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michel Dänzer <michel@daenzer.net>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180203051302.9974-9-dhinakaran.pandiyan@intel.com
Diffstat (limited to 'include/drm/drm_vblank.h')
| -rw-r--r-- | include/drm/drm_vblank.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/drm/drm_vblank.h b/include/drm/drm_vblank.h index a4c3b0a0a197..16d46e2a6854 100644 --- a/include/drm/drm_vblank.h +++ b/include/drm/drm_vblank.h @@ -180,6 +180,8 @@ void drm_crtc_vblank_off(struct drm_crtc *crtc); void drm_crtc_vblank_reset(struct drm_crtc *crtc); void drm_crtc_vblank_on(struct drm_crtc *crtc); u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc); +void drm_vblank_restore(struct drm_device *dev, unsigned int pipe); +void drm_crtc_vblank_restore(struct drm_crtc *crtc); bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, unsigned int pipe, int *max_error, |