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Commit 36693f3c authored by Laurent Pinchart's avatar Laurent Pinchart
Browse files

drm: rcar-du: Wait for page flip completion when turning the CRTC off 



Turning a CRTC off will prevent a queued page flip from ever completing,
potentially confusing userspace. Wait for queued page flips to complete
before turning the CRTC off to avoid this.

Signed-off-by: default avatarLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
parent 17f6b8a0

drivers/gpu/drm/rcar-du/rcar_du_crtc.c

+35 −0
Original line number Diff line number Diff line
@@ -300,11 +300,39 @@ static void rcar_du_crtc_finish_page_flip(struct rcar_du_crtc *rcrtc) 


	spin_lock_irqsave(&dev->event_lock, flags);

	drm_send_vblank_event(dev, rcrtc->index, event);

	wake_up(&rcrtc->flip_wait);

	spin_unlock_irqrestore(&dev->event_lock, flags);



	drm_vblank_put(dev, rcrtc->index);

}



static bool rcar_du_crtc_page_flip_pending(struct rcar_du_crtc *rcrtc)

{

	struct drm_device *dev = rcrtc->crtc.dev;

	unsigned long flags;

	bool pending;



	spin_lock_irqsave(&dev->event_lock, flags);

	pending = rcrtc->event != NULL;

	spin_unlock_irqrestore(&dev->event_lock, flags);



	return pending;

}



static void rcar_du_crtc_wait_page_flip(struct rcar_du_crtc *rcrtc)

{

	struct rcar_du_device *rcdu = rcrtc->group->dev;



	if (wait_event_timeout(rcrtc->flip_wait,

			       !rcar_du_crtc_page_flip_pending(rcrtc),

			       msecs_to_jiffies(50)))

		return;



	dev_warn(rcdu->dev, "page flip timeout\n");



	rcar_du_crtc_finish_page_flip(rcrtc);

}



/* -----------------------------------------------------------------------------

 * Start/Stop and Suspend/Resume

 */
@@ -365,6 +393,11 @@ static void rcar_du_crtc_stop(struct rcar_du_crtc *rcrtc) 
	if (!rcrtc->started)

		return;



	/* Wait for page flip completion before stopping the CRTC as userspace

	 * excepts page flips to eventually complete.

	 */

	rcar_du_crtc_wait_page_flip(rcrtc);



	mutex_lock(&rcrtc->group->planes.lock);

	rcrtc->plane->enabled = false;

	rcar_du_crtc_update_planes(crtc);
@@ -644,6 +677,8 @@ int rcar_du_crtc_create(struct rcar_du_group *rgrp, unsigned int index) 
		return -EPROBE_DEFER;

	}



	init_waitqueue_head(&rcrtc->flip_wait);



	rcrtc->group = rgrp;

	rcrtc->mmio_offset = mmio_offsets[index];

	rcrtc->index = index;

drivers/gpu/drm/rcar-du/rcar_du_crtc.h

+3 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
#define __RCAR_DU_CRTC_H__



#include <linux/mutex.h>

#include <linux/wait.h>



#include <drm/drmP.h>

#include <drm/drm_crtc.h>
@@ -32,6 +33,8 @@ struct rcar_du_crtc { 
	bool started;



	struct drm_pending_vblank_event *event;

	wait_queue_head_t flip_wait;



	unsigned int outputs;

	int dpms;