[PATCH 2/2] drm/radeon: Add lock on drm_helper_resume_force_mode

[Peter Huewe]

mode_config should be locked when calling drm_helper_resume_force_mode.
This patch adds the lock, similar to #927a2f119.

Cc: stable at kernel.org
Signed-off-by: Peter Huewe <peterhuewe at gmx.de>
---
 drivers/gpu/drm/radeon/radeon_device.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
index ea7df16..d287f23 100644
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -973,7 +973,9 @@ int radeon_resume_kms(struct drm_device *dev)
 	/* reset hpd state */
 	radeon_hpd_init(rdev);
 	/* blat the mode back in */
+	mutex_lock(&dev->mode_config.mutex);
 	drm_helper_resume_force_mode(dev);
+	mutex_unlock(&dev->mode_config.mutex);
 	/* turn on display hw */
 	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
 		drm_helper_connector_dpms(connector, DRM_MODE_DPMS_ON);
-- 
1.7.3.4