drm/radeon/kms: switch to condition waiting for reclocking

We tried to implement interruptible waiting with timeout (it was broken
anyway) which was not a good idea as explained by Andrew. It's possible
to avoid using additional variable but actually it inroduces using more
complex in-kernel tools. So simply add one variable for condition.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_pm.c b/drivers/gpu/drm/radeon/radeon_pm.c
index d4d1c39..d800b86 100644
--- a/drivers/gpu/drm/radeon/radeon_pm.c
+++ b/drivers/gpu/drm/radeon/radeon_pm.c
@@ -353,10 +353,12 @@
 		rdev->pm.req_vblank |= (1 << 1);
 		drm_vblank_get(rdev->ddev, 1);
 	}
-	if (rdev->pm.active_crtcs)
-		wait_event_interruptible_timeout(
-			rdev->irq.vblank_queue, 0,
+	if (rdev->pm.active_crtcs) {
+		rdev->pm.vblank_sync = false;
+		wait_event_timeout(
+			rdev->irq.vblank_queue, rdev->pm.vblank_sync,
 			msecs_to_jiffies(RADEON_WAIT_VBLANK_TIMEOUT));
+	}
 	if (rdev->pm.req_vblank & (1 << 0)) {
 		rdev->pm.req_vblank &= ~(1 << 0);
 		drm_vblank_put(rdev->ddev, 0);