Merge branch 'topic/drm-vblank-rework' into drm-intel-next-queued

Pull in the drm vblank rework from Ville and me. drm core parts acked
by Dave Airlie

Conflicts:
	drivers/gpu/drm/i915/intel_display.c

Just a bit of fun around the placement of drm_vblank_on. This merge
resolution has been tested in drm-intel-nightly for a while already.

Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 13 insertions, 4 deletions

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 04d3fd3658f..e95ed5805f0 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -45,13 +45,13 @@ static LIST_HEAD(kernel_fb_helper_list);
  * DOC: fbdev helpers
  *
  * The fb helper functions are useful to provide an fbdev on top of a drm kernel
- * mode setting driver. They can be used mostly independantely from the crtc
+ * mode setting driver. They can be used mostly independently from the crtc
  * helper functions used by many drivers to implement the kernel mode setting
  * interfaces.
  *
  * Initialization is done as a three-step process with drm_fb_helper_init(),
  * drm_fb_helper_single_add_all_connectors() and drm_fb_helper_initial_config().
- * Drivers with fancier requirements than the default beheviour can override the
+ * Drivers with fancier requirements than the default behaviour can override the
  * second step with their own code.  Teardown is done with drm_fb_helper_fini().
  *
  * At runtime drivers should restore the fbdev console by calling
@@ -59,7 +59,7 @@ static LIST_HEAD(kernel_fb_helper_list);
  * should also notify the fb helper code from updates to the output
  * configuration by calling drm_fb_helper_hotplug_event(). For easier
  * integration with the output polling code in drm_crtc_helper.c the modeset
- * code proves a ->output_poll_changed callback.
+ * code provides a ->output_poll_changed callback.
  *
  * All other functions exported by the fb helper library can be used to
  * implement the fbdev driver interface by the driver.
@@ -326,12 +326,21 @@ static bool drm_fb_helper_force_kernel_mode(void)
 		return false;
 
 	list_for_each_entry(helper, &kernel_fb_helper_list, kernel_fb_list) {
-		if (helper->dev->switch_power_state == DRM_SWITCH_POWER_OFF)
+		struct drm_device *dev = helper->dev;
+
+		if (dev->switch_power_state == DRM_SWITCH_POWER_OFF)
+			continue;
+
+		if (!mutex_trylock(&dev->mode_config.mutex)) {
+			error = true;
 			continue;
+		}
 
 		ret = drm_fb_helper_restore_fbdev_mode(helper);
 		if (ret)
 			error = true;
+
+		mutex_unlock(&dev->mode_config.mutex);
 	}
 	return error;
 }