Commit b1ce7fe4 authored by Geert Uytterhoeven's avatar Geert Uytterhoeven
Browse files

drm: renesas: shmobile: Wait for page flip when turning 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.

Reviewed-by: default avatarLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/c97d5859c43fa36043c61de28d67688ebe345092.1694767209.git.geert+renesas@glider.be
parent a87e3159

drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c

+37 −0
Original line number Diff line number Diff line
@@ -50,11 +50,40 @@ void shmob_drm_crtc_finish_page_flip(struct shmob_drm_crtc *scrtc) 
	scrtc->event = NULL;

	if (event) {

		drm_crtc_send_vblank_event(&scrtc->base, event);

		wake_up(&scrtc->flip_wait);

		drm_crtc_vblank_put(&scrtc->base);

	}

	spin_unlock_irqrestore(&dev->event_lock, flags);

}



static bool shmob_drm_crtc_page_flip_pending(struct shmob_drm_crtc *scrtc)

{

	struct drm_device *dev = scrtc->base.dev;

	unsigned long flags;

	bool pending;



	spin_lock_irqsave(&dev->event_lock, flags);

	pending = scrtc->event != NULL;

	spin_unlock_irqrestore(&dev->event_lock, flags);



	return pending;

}



static void shmob_drm_crtc_wait_page_flip(struct shmob_drm_crtc *scrtc)

{

	struct drm_crtc *crtc = &scrtc->base;

	struct shmob_drm_device *sdev = to_shmob_device(crtc->dev);



	if (wait_event_timeout(scrtc->flip_wait,

			       !shmob_drm_crtc_page_flip_pending(scrtc),

			       msecs_to_jiffies(50)))

		return;



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



	shmob_drm_crtc_finish_page_flip(scrtc);

}



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

 * CRTC

 */
@@ -253,6 +282,12 @@ static void shmob_drm_crtc_stop(struct shmob_drm_crtc *scrtc) 
	if (!scrtc->started)

		return;



	/*

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

	 * expects page flips to eventually complete.

	 */

	shmob_drm_crtc_wait_page_flip(scrtc);



	/* Stop the LCDC. */

	shmob_drm_crtc_start_stop(scrtc, false);
@@ -463,6 +498,8 @@ int shmob_drm_crtc_create(struct shmob_drm_device *sdev) 
	unsigned int i;

	int ret;



	init_waitqueue_head(&sdev->crtc.flip_wait);



	sdev->crtc.dpms = DRM_MODE_DPMS_OFF;



	primary = shmob_drm_plane_create(sdev, DRM_PLANE_TYPE_PRIMARY, 0);

drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.h

+3 −0
Original line number Diff line number Diff line
@@ -14,6 +14,8 @@ 
#include <drm/drm_connector.h>

#include <drm/drm_encoder.h>



#include <linux/wait.h>



#include <video/videomode.h>



struct drm_pending_vblank_event;
@@ -24,6 +26,7 @@ struct shmob_drm_crtc { 
	struct drm_crtc base;



	struct drm_pending_vblank_event *event;

	wait_queue_head_t flip_wait;

	int dpms;



	const struct shmob_drm_format_info *format;