[PATCH 5/6] drm/radeon/pm: Handle failure of drm_vblank_get.

[Mario Kleiner]

Make sure that drm_vblank_get/put() stay balanced in
case drm_vblank_get fails, by skipping the corresponding
put.

Signed-off-by: Mario Kleiner <mario.kleiner.de at gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
Cc: michel at daenzer.net
Cc: dri-devel at lists.freedesktop.org
Cc: alexander.deucher at amd.com
Cc: christian.koenig at amd.com
---
 drivers/gpu/drm/radeon/radeon_pm.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_pm.c b/drivers/gpu/drm/radeon/radeon_pm.c
index 59abebd..a94979f 100644
--- a/drivers/gpu/drm/radeon/radeon_pm.c
+++ b/drivers/gpu/drm/radeon/radeon_pm.c
@@ -276,8 +276,12 @@ static void radeon_pm_set_clocks(struct radeon_device *rdev)
 	if (rdev->irq.installed) {
 		for (i = 0; i < rdev->num_crtc; i++) {
 			if (rdev->pm.active_crtcs & (1 << i)) {
-				rdev->pm.req_vblank |= (1 << i);
-				drm_vblank_get(rdev->ddev, i);
+				/* This can fail if a modeset is in progress */
+				if (drm_vblank_get(rdev->ddev, i) == 0)
+					rdev->pm.req_vblank |= (1 << i);
+				else
+					DRM_DEBUG_DRIVER("crtc %d no vblank, can glitch\n",
+							 i);
 			}
 		}
 	}
-- 
1.9.1