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drm/exynos: fix lockdep for event_lock wrt. vbl_time_lock

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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: Imre Deak <imre.deak@intel.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
This commit is contained in:
Imre Deak 2012-11-02 13:30:49 +02:00 committed by Inki Dae
parent e1f48ee58a
commit 9fb7dff5ec
2 changed files with 0 additions and 24 deletions
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12
drivers/gpu/drm/exynos/exynos_drm_fimd.c
View File

@ -623,7 +623,6 @@ static void fimd_finish_pageflip(struct drm_device *drm_dev, int crtc)
struct drm_pending_vblank_event *e, *t;
struct timeval now;
unsigned long flags;
bool is_checked = false;
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)
continue;
is_checked = true;
do_gettimeofday(&now);
e->event.sequence = 0;
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);
}
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);
}

12
drivers/gpu/drm/exynos/exynos_drm_vidi.c
View File

@ -382,7 +382,6 @@ static void vidi_finish_pageflip(struct drm_device *drm_dev, int crtc)
struct drm_pending_vblank_event *e, *t;
struct timeval now;
unsigned long flags;
bool is_checked = false;
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)
continue;
is_checked = true;
do_gettimeofday(&now);
e->event.sequence = 0;
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);
}
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);
}