[Intel-gfx] [PATCH 4/4] drm/i915: Ignore LVDS EDID when it is unavailabe or invalid

[Zhenyu Wang]

From: Zhao Yakui <yakui.zhao at intel.com>

This trys to shut up complains about invalid LVDS EDID during
mode probe, but uses fixed panel mode directly for panels with
broken EDID.

https://bugs.freedesktop.org/show_bug.cgi?id=23099
https://bugs.freedesktop.org/show_bug.cgi?id=26395

Signed-off-by: Zhao Yakui <yakui.zhao at intel.com>
Tested-by: Sitsofe Wheeler <sitsofe at yahoo.com>
Signed-off-by: Zhenyu Wang <zhenyuw at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h   |    2 ++
 drivers/gpu/drm/i915/intel_lvds.c |   13 +++++++++----
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index b7cb4aa..6960849 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -611,6 +611,8 @@ typedef struct drm_i915_private {
 	/* Reclocking support */
 	bool render_reclock_avail;
 	bool lvds_downclock_avail;
+	/* indicate whether the LVDS EDID is OK */
+	bool lvds_edid_good;
 	/* indicates the reduced downclock for LVDS*/
 	int lvds_downclock;
 	struct work_struct idle_work;
diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index 3fa088c..8bbcb32 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -638,10 +638,12 @@ static int intel_lvds_get_modes(struct drm_connector *connector)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	int ret = 0;
 
-	ret = intel_ddc_get_modes(intel_encoder);
+	if (dev_priv->lvds_edid_good) {
+		ret = intel_ddc_get_modes(intel_encoder);
 
-	if (ret)
-		return ret;
+		if (ret)
+			return ret;
+	}
 
 	/* Didn't get an EDID, so
 	 * Set wide sync ranges so we get all modes
@@ -1064,7 +1066,10 @@ void intel_lvds_init(struct drm_device *dev)
 	 * Attempt to get the fixed panel mode from DDC.  Assume that the
 	 * preferred mode is the right one.
 	 */
-	intel_ddc_get_modes(intel_encoder);
+	dev_priv->lvds_edid_good = true;
+
+	if (!intel_ddc_get_modes(intel_encoder))
+		dev_priv->lvds_edid_good = false;
 
 	list_for_each_entry(scan, &connector->probed_modes, head) {
 		mutex_lock(&dev->mode_config.mutex);
-- 
1.6.3.3