drm: Make the connector dpms callback return a value, v2.

This is required to properly handle failing dpms calls.
When making a wait in i915 interruptible, I've noticed
that the dpms sequence could fail with -ERESTARTSYS because
it was waiting interruptibly for flips. So from now on
allow drivers to fail in their connector dpms callback.

Encoder and crtc dpms callbacks are unaffected.

Changes since v1:
- Update kerneldoc for the drm helper functions.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
[danvet: Resolve conflicts due to different merge order.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 6 insertions, 3 deletions

diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
index d3d038f05bf7..ef534758a02c 100644
--- a/drivers/gpu/drm/drm_crtc_helper.c
+++ b/drivers/gpu/drm/drm_crtc_helper.c
@@ -762,15 +762,18 @@ static int drm_helper_choose_crtc_dpms(struct drm_crtc *crtc)
  * implementing the DPMS connector attribute. It computes the new desired DPMS
  * state for all encoders and crtcs in the output mesh and calls the ->dpms()
  * callback provided by the driver appropriately.
+ *
+ * Returns:
+ * Always returns 0.
  */
-void drm_helper_connector_dpms(struct drm_connector *connector, int mode)
+int drm_helper_connector_dpms(struct drm_connector *connector, int mode)
 {
 	struct drm_encoder *encoder = connector->encoder;
 	struct drm_crtc *crtc = encoder ? encoder->crtc : NULL;
 	int old_dpms, encoder_dpms = DRM_MODE_DPMS_OFF;
 
 	if (mode == connector->dpms)
-		return;
+		return 0;
 
 	old_dpms = connector->dpms;
 	connector->dpms = mode;
@@ -802,7 +805,7 @@ void drm_helper_connector_dpms(struct drm_connector *connector, int mode)
 		}
 	}
 
-	return;
+	return 0;
 }
 EXPORT_SYMBOL(drm_helper_connector_dpms);