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

commit 8c241fef 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>

drivers/gpu/drm/i915/intel_dp.c

@@ -1683,6 +1683,31 @@ g4x_dp_detect(struct intel_dp *intel_dp)
 	return intel_dp_detect_dpcd(intel_dp);
 }
 
+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.
  *
@@ -1715,7 +1740,7 @@ intel_dp_detect(struct drm_connector *connector, bool force)
 	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;
@@ -1736,7 +1761,7 @@ static int intel_dp_get_modes(struct drm_connector *connector)
 	/* 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;
@@ -1772,7 +1797,7 @@ intel_dp_detect_audio(struct drm_connector *connector)
 	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);