drm/exynos: use wait_event_timeout() for safety usage

There could be the case that the page flip operation isn't finished correctly
with some abnormal condition such as panel reset. So this patch replaces
wait_event() with wait_event_timeout() to avoid waiting for page flip completion
infinitely.
And clears exynos_crtc->pending_flip in exynos_drm_crtc_page_flip()
when exynos_drm_crtc_mode_set_commit() is failed.

Change-Id: Ib110ff1d6089394da37ba5a8375a4efdd6128672
Signed-off-by: YoungJun Cho <yj44.cho@samsung.com>
Acked-by: Inki Dae <inki.dae@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

diff --git a/drivers/gpu/drm/exynos/exynos_drm_crtc.c b/drivers/gpu/drm/exynos/exynos_drm_crtc.c
index bc69436..1c7dd47 100644 (file)
--- a/drivers/gpu/drm/exynos/exynos_drm_crtc.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_crtc.c
@@ -85,8 +85,10 @@ static void exynos_drm_crtc_dpms(struct drm_crtc *crtc, int mode)
 
        if (mode > DRM_MODE_DPMS_ON) {
                /* wait for the completion of page flip. */
-               wait_event(exynos_crtc->pending_flip_queue,
-                               atomic_read(&exynos_crtc->pending_flip) == 0);
+               if (!wait_event_timeout(exynos_crtc->pending_flip_queue,
+                               !atomic_read(&exynos_crtc->pending_flip),
+                               HZ/20))
+                       atomic_set(&exynos_crtc->pending_flip, 0);
                drm_vblank_off(crtc->dev, exynos_crtc->pipe);
        }
 
@@ -353,6 +355,7 @@ out_fence:
                        spin_lock_irq(&dev->event_lock);
                        drm_vblank_put(dev, exynos_crtc->pipe);
                        list_del(&event->base.link);
+                       atomic_set(&exynos_crtc->pending_flip, 0);
                        spin_unlock_irq(&dev->event_lock);
 
                        mutex_unlock(&dev->struct_mutex);