[PATCH 2/2] Check if the bus is valid prior to discovering edid.

Eugeni Dodonov eugeni.dodonov at intel.com
Fri Oct 7 15:00:42 PDT 2011


This adds a new function intel_drm_get_valid_edid, which is used instead
of drm_get_edid within the i915 driver.

It does a similar check to the one in previous patch, but it is limited to
i915 driver.

The check is similar to the first part of EDID discovery performed by the
drm_do_probe_ddc_edid. In case the i2c_transfer fails with the -ENXIO
result, we know that the i2c_algo_bit was unable to locate the hardware,
so we give up on further edid discovery.

They should also fix https://bugs.freedesktop.org/show_bug.cgi?id=41059

v2: change printk level to KERN_DEBUG to avoid filling up dmesg

Signed-off-by: Eugeni Dodonov <eugeni.dodonov at intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c    |    4 ++--
 drivers/gpu/drm/i915/intel_drv.h   |    2 ++
 drivers/gpu/drm/i915/intel_hdmi.c  |    4 ++--
 drivers/gpu/drm/i915/intel_i2c.c   |   33 +++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_lvds.c  |    2 +-
 drivers/gpu/drm/i915/intel_modes.c |    2 +-
 drivers/gpu/drm/i915/intel_sdvo.c  |    4 ++--
 7 files changed, 43 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 44fef5e..dd0d8b1 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1715,7 +1715,7 @@ 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_drm_get_valid_edid(connector, &intel_dp->adapter);
 		if (edid) {
 			intel_dp->has_audio = drm_detect_monitor_audio(edid);
 			connector->display_info.raw_edid = NULL;
@@ -1772,7 +1772,7 @@ 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_drm_get_valid_edid(connector, &intel_dp->adapter);
 	if (edid) {
 		has_audio = drm_detect_monitor_audio(edid);
 
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index fe1099d..d80a9b0 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -264,6 +264,8 @@ struct intel_fbc_work {
 	int interval;
 };
 
+struct edid * intel_drm_get_valid_edid(struct drm_connector *connector,
+		struct i2c_adapter *adapter);
 int intel_ddc_get_modes(struct drm_connector *c, struct i2c_adapter *adapter);
 extern bool intel_ddc_probe(struct intel_encoder *intel_encoder, int ddc_bus);
 
diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index 226ba83..714f2fb 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -329,7 +329,7 @@ intel_hdmi_detect(struct drm_connector *connector, bool force)
 
 	intel_hdmi->has_hdmi_sink = false;
 	intel_hdmi->has_audio = false;
-	edid = drm_get_edid(connector,
+	edid = intel_drm_get_valid_edid(connector,
 			    &dev_priv->gmbus[intel_hdmi->ddc_bus].adapter);
 
 	if (edid) {
@@ -371,7 +371,7 @@ intel_hdmi_detect_audio(struct drm_connector *connector)
 	struct edid *edid;
 	bool has_audio = false;
 
-	edid = drm_get_edid(connector,
+	edid = intel_drm_get_valid_edid(connector,
 			    &dev_priv->gmbus[intel_hdmi->ddc_bus].adapter);
 	if (edid) {
 		if (edid->input & DRM_EDID_INPUT_DIGITAL)
diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c
index d98cee6..77115b9 100644
--- a/drivers/gpu/drm/i915/intel_i2c.c
+++ b/drivers/gpu/drm/i915/intel_i2c.c
@@ -470,3 +470,36 @@ void intel_teardown_gmbus(struct drm_device *dev)
 	kfree(dev_priv->gmbus);
 	dev_priv->gmbus = NULL;
 }
+
+/**
+ * intel_drm_get_valid_edid - gets edid from existent adapters only
+ * @connector: DRM connector device to use
+ * @adapter: i2c adapter
+ *
+ * Verifies if the i2c adapter is responding to our queries before
+ * attempting to do proper communication with it. If it does,
+ * retreive the EDID with help of drm_get_edid
+ */
+struct edid *
+intel_drm_get_valid_edid(struct drm_connector *connector,
+		struct i2c_adapter *adapter)
+{
+	unsigned char out;
+	int ret;
+	struct i2c_msg msgs[] = {
+		{
+			.addr	= 0x50,
+			.flags	= 0,
+			.len	= 1,
+			.buf	= &out,
+		}
+	};
+	/* Let's try one edid transfer */
+	ret = i2c_transfer(adapter, msgs, 1);
+	if (ret == -ENXIO) {
+		printk(KERN_DEBUG "i915: adapter %s not responding: %d\n",
+				adapter->name, ret);
+		return NULL;
+	}
+	return drm_get_edid(connector, adapter);
+}
diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index 31da77f..8f59a8e 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -921,7 +921,7 @@ bool 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_lvds->edid = drm_get_edid(connector,
+	intel_lvds->edid = intel_drm_get_valid_edid(connector,
 					&dev_priv->gmbus[pin].adapter);
 	if (intel_lvds->edid) {
 		if (drm_add_edid_modes(connector,
diff --git a/drivers/gpu/drm/i915/intel_modes.c b/drivers/gpu/drm/i915/intel_modes.c
index 3b26a3b..9280343 100644
--- a/drivers/gpu/drm/i915/intel_modes.c
+++ b/drivers/gpu/drm/i915/intel_modes.c
@@ -70,7 +70,7 @@ int intel_ddc_get_modes(struct drm_connector *connector,
 	struct edid *edid;
 	int ret = 0;
 
-	edid = drm_get_edid(connector, adapter);
+	edid = intel_drm_get_valid_edid(connector, adapter);
 	if (edid) {
 		drm_mode_connector_update_edid_property(connector, edid);
 		ret = drm_add_edid_modes(connector, edid);
diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index 6348c49..8b4ac61 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -1240,7 +1240,7 @@ static struct edid *
 intel_sdvo_get_edid(struct drm_connector *connector)
 {
 	struct intel_sdvo *sdvo = intel_attached_sdvo(connector);
-	return drm_get_edid(connector, &sdvo->ddc);
+	return intel_drm_get_valid_edid(connector, &sdvo->ddc);
 }
 
 /* Mac mini hack -- use the same DDC as the analog connector */
@@ -1249,7 +1249,7 @@ intel_sdvo_get_analog_edid(struct drm_connector *connector)
 {
 	struct drm_i915_private *dev_priv = connector->dev->dev_private;
 
-	return drm_get_edid(connector,
+	return intel_drm_get_valid_edid(connector,
 			    &dev_priv->gmbus[dev_priv->crt_ddc_pin].adapter);
 }
 
-- 
1.7.6.4



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