1 files changed, 15 insertions, 2 deletions

diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
index 298ea1c453c3..2b9ba03a7c1a 100644
--- a/drivers/gpu/drm/radeon/radeon_display.c
+++ b/drivers/gpu/drm/radeon/radeon_display.c
@@ -403,7 +403,8 @@ static void radeon_flip_work_func(struct work_struct *__work)
         struct drm_crtc *crtc = &radeon_crtc->base;
         unsigned long flags;
         int r;
-        int vpos, hpos, stat, min_udelay;
+        int vpos, hpos, stat, min_udelay = 0;
+        unsigned repcnt = 4;
         struct drm_vblank_crtc *vblank = &crtc->dev->vblank[work->crtc_id];
 
         down_read(&rdev->exclusive_lock);
@@ -454,7 +455,7 @@ static void radeon_flip_work_func(struct work_struct *__work)
          * In practice this won't execute very often unless on very fast
          * machines because the time window for this to happen is very small.
          */
-        for (;;) {
+        while (radeon_crtc->enabled && repcnt--) {
                 /* GET_DISTANCE_TO_VBLANKSTART returns distance to real vblank
                  * start in hpos, and to the "fudged earlier" vblank start in
                  * vpos.
@@ -472,10 +473,22 @@ static void radeon_flip_work_func(struct work_struct *__work)
                 /* Sleep at least until estimated real start of hw vblank */
                 spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
                 min_udelay = (-hpos + 1) * max(vblank->linedur_ns / 1000, 5);
+                if (min_udelay > vblank->framedur_ns / 2000) {
+                        /* Don't wait ridiculously long - something is wrong */
+                        repcnt = 0;
+                        break;
+                }
                 usleep_range(min_udelay, 2 * min_udelay);
                 spin_lock_irqsave(&crtc->dev->event_lock, flags);
         };
 
+        if (!repcnt)
+                DRM_DEBUG_DRIVER("Delay problem on crtc %d: min_udelay %d, "
+                                 "framedur %d, linedur %d, stat %d, vpos %d, "
+                                 "hpos %d\n", work->crtc_id, min_udelay,
+                                 vblank->framedur_ns / 1000,
+                                 vblank->linedur_ns / 1000, stat, vpos, hpos);
+
         /* do the flip (mmio) */
         radeon_page_flip(rdev, radeon_crtc->crtc_id, work->base);