[PATCH 2/4] i915: fall back to ACPI EDID retrieval

[Daniel Dadap <ddadap-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>]

Fall back to retrieving the EDID via the ACPI _DDC method, when present
for notebook internal panels, when EDID retrieval via the standard EDID
paths is unsuccessful.

Signed-off-by: Daniel Dadap <ddadap-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
---
 drivers/gpu/drm/i915/display/intel_dp.c   | 8 +++++++-
 drivers/gpu/drm/i915/display/intel_lvds.c | 4 ++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 804b1d966f66..ff402cef8183 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -5657,6 +5657,7 @@ static struct edid *
 intel_dp_get_edid(struct intel_dp *intel_dp)
 {
 	struct intel_connector *intel_connector = intel_dp->attached_connector;
+	struct edid *edid;
 
 	/* use cached edid if we have one */
 	if (intel_connector->edid) {
@@ -5666,8 +5667,13 @@ intel_dp_get_edid(struct intel_dp *intel_dp)
 
 		return drm_edid_duplicate(intel_connector->edid);
 	} else
-		return drm_get_edid(&intel_connector->base,
+		edid = drm_get_edid(&intel_connector->base,
 				    &intel_dp->aux.ddc);
+
+	if (!edid && intel_dp_is_edp(intel_dp))
+		edid = drm_get_edid_acpi();
+
+	return edid;
 }
 
 static void
diff --git a/drivers/gpu/drm/i915/display/intel_lvds.c b/drivers/gpu/drm/i915/display/intel_lvds.c
index 9a067effcfa0..811eea3f5d9f 100644
--- a/drivers/gpu/drm/i915/display/intel_lvds.c
+++ b/drivers/gpu/drm/i915/display/intel_lvds.c
@@ -946,6 +946,10 @@ void intel_lvds_init(struct drm_i915_private *dev_priv)
 	else
 		edid = drm_get_edid(connector,
 				    intel_gmbus_get_adapter(dev_priv, pin));
+
+	if (!edid)
+		edid = drm_get_edid_acpi();
+
 	if (edid) {
 		if (drm_add_edid_modes(connector, edid)) {
 			drm_connector_update_edid_property(connector,
-- 
2.18.4