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Commit e8450f51 authored by Daniel Vetter's avatar Daniel Vetter
Browse files

drm/irq: Implement a generic vblank_wait function 



As usual in both a crtc index and a struct drm_crtc * version.

The function assumes that no one drivers their display below 10Hz, and
it will complain if the vblank wait takes longer than that.

v2: Also check dev->max_vblank_counter since some drivers register a
fake get_vblank_counter function.

v3: Use drm_vblank_count instead of calling the low-level
->get_vblank_counter callback. That way we'll get the sw-cooked
counter for platforms without proper vblank support and so can ditch
the max_vblank_counter check again.

v4: Review from Michel Dänzer:
- Restore lost notes about v3:
- Spelling in kerneldoc.
- Inline wait_event condition.
- s/vblank_wait/wait_one_vblank/

Cc: Michel Dänzer <michel@daenzer.net>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: default avatarMichel Dänzer <michel.daenzer@amd.com>
Reviewed-by: default avatarMatt Roper <matthew.d.roper@intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 2a0d7cfd

drivers/gpu/drm/drm_irq.c

+44 −0
Original line number Diff line number Diff line
@@ -1009,6 +1009,50 @@ void drm_crtc_vblank_put(struct drm_crtc *crtc) 
}

EXPORT_SYMBOL(drm_crtc_vblank_put);



/**

 * drm_wait_one_vblank - wait for one vblank

 * @dev: DRM device

 * @crtc: crtc index

 *

 * This waits for one vblank to pass on @crtc, using the irq driver interfaces.

 * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.

 * due to lack of driver support or because the crtc is off.

 */

void drm_wait_one_vblank(struct drm_device *dev, int crtc)

{

	int ret;

	u32 last;



	ret = drm_vblank_get(dev, crtc);

	if (WARN_ON(ret))

		return;



	last = drm_vblank_count(dev, crtc);



	ret = wait_event_timeout(dev->vblank[crtc].queue,

				 last != drm_vblank_count(dev, crtc),

				 msecs_to_jiffies(100));



	WARN_ON(ret == 0);



	drm_vblank_put(dev, crtc);

}

EXPORT_SYMBOL(drm_wait_one_vblank);



/**

 * drm_crtc_wait_one_vblank - wait for one vblank

 * @crtc: DRM crtc

 *

 * This waits for one vblank to pass on @crtc, using the irq driver interfaces.

 * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.

 * due to lack of driver support or because the crtc is off.

 */

void drm_crtc_wait_one_vblank(struct drm_crtc *crtc)

{

	drm_wait_one_vblank(crtc->dev, drm_crtc_index(crtc));

}

EXPORT_SYMBOL(drm_crtc_wait_one_vblank);



/**

 * drm_vblank_off - disable vblank events on a CRTC

 * @dev: DRM device

include/drm/drmP.h

+2 −0
Original line number Diff line number Diff line
@@ -1327,6 +1327,8 @@ extern int drm_vblank_get(struct drm_device *dev, int crtc); 
extern void drm_vblank_put(struct drm_device *dev, int crtc);

extern int drm_crtc_vblank_get(struct drm_crtc *crtc);

extern void drm_crtc_vblank_put(struct drm_crtc *crtc);

extern void drm_wait_one_vblank(struct drm_device *dev, int crtc);

extern void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);

extern void drm_vblank_off(struct drm_device *dev, int crtc);

extern void drm_vblank_on(struct drm_device *dev, int crtc);

extern void drm_crtc_vblank_off(struct drm_crtc *crtc);