diff options
Diffstat (limited to 'include/drm/drm_vblank.h')
| -rw-r--r-- | include/drm/drm_vblank.h | 30 |
1 files changed, 26 insertions, 4 deletions
diff --git a/include/drm/drm_vblank.h b/include/drm/drm_vblank.h index d25a9603ab57..e528bb2f659d 100644 --- a/include/drm/drm_vblank.h +++ b/include/drm/drm_vblank.h @@ -95,7 +95,7 @@ struct drm_vblank_crtc { /** * @queue: Wait queue for vblank waiters. */ - wait_queue_head_t queue; /**< VBLANK wait queue */ + wait_queue_head_t queue; /** * @disable_timer: Disable timer for the delayed vblank disabling * hysteresis logic. Vblank disabling is controlled through the @@ -107,7 +107,7 @@ struct drm_vblank_crtc { /** * @seqlock: Protect vblank count and time. */ - seqlock_t seqlock; /* protects vblank count and time */ + seqlock_t seqlock; /** * @count: Current software vblank counter. @@ -123,12 +123,32 @@ struct drm_vblank_crtc { * this refcount reaches 0 can the hardware interrupt be disabled using * @disable_timer. */ - atomic_t refcount; /* number of users of vblank interruptsper crtc */ + atomic_t refcount; /** * @last: Protected by &drm_device.vbl_lock, used for wraparound handling. */ u32 last; /** + * @max_vblank_count: + * + * Maximum value of the vblank registers for this crtc. This value +1 + * will result in a wrap-around of the vblank register. It is used + * by the vblank core to handle wrap-arounds. + * + * If set to zero the vblank core will try to guess the elapsed vblanks + * between times when the vblank interrupt is disabled through + * high-precision timestamps. That approach is suffering from small + * races and imprecision over longer time periods, hence exposing a + * hardware vblank counter is always recommended. + * + * This is the runtime configurable per-crtc maximum set through + * drm_crtc_set_max_vblank_count(). If this is used the driver + * must leave the device wide &drm_device.max_vblank_count at zero. + * + * If non-zero, &drm_crtc_funcs.get_vblank_counter must be set. + */ + u32 max_vblank_count; + /** * @inmodeset: Tracks whether the vblank is disabled due to a modeset. * For legacy driver bit 2 additionally tracks whether an additional * temporary vblank reference has been acquired to paper over the @@ -136,7 +156,7 @@ struct drm_vblank_crtc { * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly * save and restore the vblank count. */ - unsigned int inmodeset; /* Display driver is setting mode */ + unsigned int inmodeset; /** * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this * structure. @@ -206,4 +226,6 @@ bool drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, void drm_calc_timestamping_constants(struct drm_crtc *crtc, const struct drm_display_mode *mode); wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc); +void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc, + u32 max_vblank_count); #endif |