drm/ast: use drm_modeset_lock_all

Just a call to drm_helper_resume_force_mode, obviously wants full
locking for that.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/gpu/drm/ast/ast_drv.c b/drivers/gpu/drm/ast/ast_drv.c
index 2d2c2f8d6dc6..df0d0a08097a 100644
--- a/drivers/gpu/drm/ast/ast_drv.c
+++ b/drivers/gpu/drm/ast/ast_drv.c
@@ -94,9 +94,9 @@ static int ast_drm_thaw(struct drm_device *dev)
         ast_post_gpu(dev);
 
         drm_mode_config_reset(dev);
-        mutex_lock(&dev->mode_config.mutex);
+        drm_modeset_lock_all(dev);
         drm_helper_resume_force_mode(dev);
-        mutex_unlock(&dev->mode_config.mutex);
+        drm_modeset_unlock_all(dev);
 
         console_lock();
         ast_fbdev_set_suspend(dev, 0);