diff options
Diffstat (limited to 'include/drm/drm_vblank.h')
| -rw-r--r-- | include/drm/drm_vblank.h | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/include/drm/drm_vblank.h b/include/drm/drm_vblank.h index 9fe4ba8bc622..c16c44052b3d 100644 --- a/include/drm/drm_vblank.h +++ b/include/drm/drm_vblank.h @@ -109,9 +109,20 @@ struct drm_vblank_crtc { seqlock_t seqlock; /** - * @count: Current software vblank counter. + * @count: + * + * Current software vblank counter. + * + * Note that for a given vblank counter value drm_crtc_handle_vblank() + * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time() + * provide a barrier: Any writes done before calling + * drm_crtc_handle_vblank() will be visible to callers of the later + * functions, iff the vblank count is the same or a later one. + * + * IMPORTANT: This guarantee requires barriers, therefor never access + * this field directly. Use drm_crtc_vblank_count() instead. */ - u64 count; + atomic64_t count; /** * @time: Vblank timestamp corresponding to @count. */ |