drm/i915: Wrap DP EDID fetch functions to enable eDP panel power

commit 8c241fef3e6f69f3f675678ae03599ece3f562e2 upstream.

Talking to the eDP DDC channel requires that the panel be powered
up. Wrap both the EDID and modes fetch code with calls to turn the vdd
power on and back off.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index e2aced6..14264a8 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1658,6 +1658,31 @@
 	return status;
 }
 
+static struct edid *
+intel_dp_get_edid(struct drm_connector *connector, struct i2c_adapter *adapter)
+{
+	struct intel_dp *intel_dp = intel_attached_dp(connector);
+	struct edid	*edid;
+
+	ironlake_edp_panel_vdd_on(intel_dp);
+	edid = drm_get_edid(connector, adapter);
+	ironlake_edp_panel_vdd_off(intel_dp);
+	return edid;
+}
+
+static int
+intel_dp_get_edid_modes(struct drm_connector *connector, struct i2c_adapter *adapter)
+{
+	struct intel_dp *intel_dp = intel_attached_dp(connector);
+	int	ret;
+
+	ironlake_edp_panel_vdd_on(intel_dp);
+	ret = intel_ddc_get_modes(connector, adapter);
+	ironlake_edp_panel_vdd_off(intel_dp);
+	return ret;
+}
+
+
 /**
  * Uses CRT_HOTPLUG_EN and CRT_HOTPLUG_STAT to detect DP connection.
  *
@@ -1684,7 +1709,7 @@
 	if (intel_dp->force_audio) {
 		intel_dp->has_audio = intel_dp->force_audio > 0;
 	} else {
-		edid = drm_get_edid(connector, &intel_dp->adapter);
+		edid = intel_dp_get_edid(connector, &intel_dp->adapter);
 		if (edid) {
 			intel_dp->has_audio = drm_detect_monitor_audio(edid);
 			connector->display_info.raw_edid = NULL;
@@ -1705,7 +1730,7 @@
 	/* We should parse the EDID data and find out if it has an audio sink
 	 */
 
-	ret = intel_ddc_get_modes(connector, &intel_dp->adapter);
+	ret = intel_dp_get_edid_modes(connector, &intel_dp->adapter);
 	if (ret) {
 		if (is_edp(intel_dp) && !dev_priv->panel_fixed_mode) {
 			struct drm_display_mode *newmode;
@@ -1741,7 +1766,7 @@
 	struct edid *edid;
 	bool has_audio = false;
 
-	edid = drm_get_edid(connector, &intel_dp->adapter);
+	edid = intel_dp_get_edid(connector, &intel_dp->adapter);
 	if (edid) {
 		has_audio = drm_detect_monitor_audio(edid);