diff options
Diffstat (limited to 'include/drm/drmP.h')
| -rw-r--r-- | include/drm/drmP.h | 37 |
1 files changed, 32 insertions, 5 deletions
diff --git a/include/drm/drmP.h b/include/drm/drmP.h index 39df16af7a4a..3aa3809ab524 100644 --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -387,22 +387,49 @@ struct drm_device { bool irq_enabled; int irq; - /* + /** + * @vblank_disable_immediate: + * * If true, vblank interrupt will be disabled immediately when the * refcount drops to zero, as opposed to via the vblank disable * timer. - * This can be set to true it the hardware has a working vblank - * counter and the driver uses drm_vblank_on() and drm_vblank_off() - * appropriately. + * + * This can be set to true it the hardware has a working vblank counter + * with high-precision timestamping (otherwise there are races) and the + * driver uses drm_crtc_vblank_on() and drm_crtc_vblank_off() + * appropriately. See also @max_vblank_count and + * &drm_crtc_funcs.get_vblank_counter. */ bool vblank_disable_immediate; - /* array of size num_crtcs */ + /** + * @vblank: + * + * Array of vblank tracking structures, one per &struct drm_crtc. For + * historical reasons (vblank support predates kernel modesetting) this + * is free-standing and not part of &struct drm_crtc itself. It must be + * initialized explicitly by calling drm_vblank_init(). + */ struct drm_vblank_crtc *vblank; spinlock_t vblank_time_lock; /**< Protects vblank count and time updates during vblank enable/disable */ spinlock_t vbl_lock; + /** + * @max_vblank_count: + * + * Maximum value of the vblank registers. 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. + * + * If non-zeor, &drm_crtc_funcs.get_vblank_counter must be set. + */ u32 max_vblank_count; /**< size of vblank counter register */ /** |