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Commit 9fb7dff5 authored by Imre Deak's avatar Imre Deak Committed by Inki Dae
Browse files

drm/exynos: fix lockdep for event_lock wrt. vbl_time_lock 



Currently the exynos driver calls drm_vblank_off() with the event_lock
held, while drm_vblank_off() will lock vbl_time and vblank_time_lock.
This lock dependency chain conflicts with the one in drm_handle_vblank()
where we first lock vblank_time_lock and then the event_lock.

Fix this by removing the above drm_vblank_off() calls which are in fact
never executed: drm_dev->vblank_disable_allowed is only ever non-zero
during driver init, until it's set in {fimd,vidi}_subdrv_probe. Both the
driver init and open code is protected by drm_global_mutex, so the
earliest page flip ioctl can happen only after vblank_disable_allowed is
set to 1. Thus {fimd,vidi}_finish_pageflip - with pending flip events -
will always get called with vblank_disable_allowed being 1.

Signed-off-by: default avatarImre Deak <imre.deak@intel.com>
Signed-off-by: default avatarInki Dae <inki.dae@samsung.com>
Signed-off-by: default avatarKyungmin Park <kyungmin.park@samsung.com>
parent e1f48ee5

drivers/gpu/drm/exynos/exynos_drm_fimd.c

+0 −12
Original line number Original line Diff line number Diff line
@@ -623,7 +623,6 @@ static void fimd_finish_pageflip(struct drm_device *drm_dev, int crtc) 
	struct drm_pending_vblank_event *e, *t;

	struct drm_pending_vblank_event *e, *t;

	struct timeval now;

	struct timeval now;

	unsigned long flags;

	unsigned long flags;

	bool is_checked = false;





	spin_lock_irqsave(&drm_dev->event_lock, flags);

	spin_lock_irqsave(&drm_dev->event_lock, flags);
@@ -633,8 +632,6 @@ static void fimd_finish_pageflip(struct drm_device *drm_dev, int crtc) 
		if (crtc != e->pipe)

		if (crtc != e->pipe)

			continue;

			continue;





		is_checked = true;



		do_gettimeofday(&now);

		do_gettimeofday(&now);

		e->event.sequence = 0;

		e->event.sequence = 0;

		e->event.tv_sec = now.tv_sec;

		e->event.tv_sec = now.tv_sec;
@@ -645,15 +642,6 @@ static void fimd_finish_pageflip(struct drm_device *drm_dev, int crtc) 
		drm_vblank_put(drm_dev, crtc);

		drm_vblank_put(drm_dev, crtc);

	}

	}





	if (is_checked) {

		/*

		 * don't off vblank if vblank_disable_allowed is 1,

		 * because vblank would be off by timer handler.

		 */

		if (!drm_dev->vblank_disable_allowed)

			drm_vblank_off(drm_dev, crtc);

	}



	spin_unlock_irqrestore(&drm_dev->event_lock, flags);

	spin_unlock_irqrestore(&drm_dev->event_lock, flags);

}

}

drivers/gpu/drm/exynos/exynos_drm_vidi.c

+0 −12
Original line number Original line Diff line number Diff line
@@ -382,7 +382,6 @@ static void vidi_finish_pageflip(struct drm_device *drm_dev, int crtc) 
	struct drm_pending_vblank_event *e, *t;

	struct drm_pending_vblank_event *e, *t;

	struct timeval now;

	struct timeval now;

	unsigned long flags;

	unsigned long flags;

	bool is_checked = false;





	spin_lock_irqsave(&drm_dev->event_lock, flags);

	spin_lock_irqsave(&drm_dev->event_lock, flags);
@@ -392,8 +391,6 @@ static void vidi_finish_pageflip(struct drm_device *drm_dev, int crtc) 
		if (crtc != e->pipe)

		if (crtc != e->pipe)

			continue;

			continue;





		is_checked = true;



		do_gettimeofday(&now);

		do_gettimeofday(&now);

		e->event.sequence = 0;

		e->event.sequence = 0;

		e->event.tv_sec = now.tv_sec;

		e->event.tv_sec = now.tv_sec;
@@ -404,15 +401,6 @@ static void vidi_finish_pageflip(struct drm_device *drm_dev, int crtc) 
		drm_vblank_put(drm_dev, crtc);

		drm_vblank_put(drm_dev, crtc);

	}

	}





	if (is_checked) {

		/*

		 * don't off vblank if vblank_disable_allowed is 1,

		 * because vblank would be off by timer handler.

		 */

		if (!drm_dev->vblank_disable_allowed)

			drm_vblank_off(drm_dev, crtc);

	}



	spin_unlock_irqrestore(&drm_dev->event_lock, flags);

	spin_unlock_irqrestore(&drm_dev->event_lock, flags);

}

}