This is a note to let you know that I've just added the patch titled
drm/i915: fall back to bit-banging if GMBUS fails in CRT EDID reads
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-i915-fall-back-to-bit-banging-if-gmbus-fails-in-crt-edid-reads.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From f1a2f5b7c5f0941d23eef0a095c0b99bf8d051e6 Mon Sep 17 00:00:00 2001
From: Jani Nikula <[email protected]>
Date: Mon, 13 Aug 2012 13:22:35 +0300
Subject: drm/i915: fall back to bit-banging if GMBUS fails in CRT EDID reads
From: Jani Nikula <[email protected]>
commit f1a2f5b7c5f0941d23eef0a095c0b99bf8d051e6 upstream.
GMBUS was enabled over bit-banging as the default in commits:
commit c3dfefa0a6d235bd465309e12f4c56ea16e71111
Author: Daniel Vetter <[email protected]>
Date: Tue Feb 14 22:37:25 2012 +0100
drm/i915: reenable gmbus on gen3+ again
and
commit 0fb3f969c8683505fb7323c06bf8a999a5a45a15
Author: Daniel Vetter <[email protected]>
Date: Fri Mar 2 19:38:30 2012 +0100
drm/i915: enable gmbus on gen2
Unfortunately, GMBUS seems to fail on some CRT displays. Add a bit-banging
fallback to CRT EDID reads.
LKML-Reference: <[email protected]>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=45881
Signed-off-by: Jani Nikula <[email protected]>
Tested-by: Alex Ferrando <[email protected]>
Cc: [email protected] (for 3.4+3.5)
Signed-off-by: Daniel Vetter <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/gpu/drm/i915/intel_crt.c | 36 +++++++++++++++++++++++++++++++++---
1 file changed, 33 insertions(+), 3 deletions(-)
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -266,6 +266,36 @@ static bool intel_crt_detect_hotplug(str
return ret;
}
+static struct edid *intel_crt_get_edid(struct drm_connector *connector,
+ struct i2c_adapter *i2c)
+{
+ struct edid *edid;
+
+ edid = drm_get_edid(connector, i2c);
+
+ if (!edid && !intel_gmbus_is_forced_bit(i2c)) {
+ DRM_DEBUG_KMS("CRT GMBUS EDID read failed, retry using GPIO
bit-banging\n");
+ intel_gmbus_force_bit(i2c, true);
+ edid = drm_get_edid(connector, i2c);
+ intel_gmbus_force_bit(i2c, false);
+ }
+
+ return edid;
+}
+
+/* local version of intel_ddc_get_modes() to use intel_crt_get_edid() */
+static int intel_crt_ddc_get_modes(struct drm_connector *connector,
+ struct i2c_adapter *adapter)
+{
+ struct edid *edid;
+
+ edid = intel_crt_get_edid(connector, adapter);
+ if (!edid)
+ return 0;
+
+ return intel_connector_update_modes(connector, edid);
+}
+
static bool intel_crt_detect_ddc(struct drm_connector *connector)
{
struct intel_crt *crt = intel_attached_crt(connector);
@@ -279,7 +309,7 @@ static bool intel_crt_detect_ddc(struct
struct edid *edid;
bool is_digital = false;
- edid = drm_get_edid(connector,
+ edid = intel_crt_get_edid(connector,
&dev_priv->gmbus[dev_priv->crt_ddc_pin].adapter);
/*
* This may be a DVI-I connector with a shared DDC
@@ -477,13 +507,13 @@ static int intel_crt_get_modes(struct dr
struct drm_i915_private *dev_priv = dev->dev_private;
int ret;
- ret = intel_ddc_get_modes(connector,
+ ret = intel_crt_ddc_get_modes(connector,
&dev_priv->gmbus[dev_priv->crt_ddc_pin].adapter);
if (ret || !IS_G4X(dev))
return ret;
/* Try to probe digital port for output in DVI-I -> VGA mode. */
- return intel_ddc_get_modes(connector,
+ return intel_crt_ddc_get_modes(connector,
&dev_priv->gmbus[GMBUS_PORT_DPB].adapter);
}
Patches currently in stable-queue which might be from [email protected] are
queue-3.4/drm-i915-fall-back-to-bit-banging-if-gmbus-fails-in-crt-edid-reads.patch
queue-3.4/drm-i915-extract-connector-update-from-intel_ddc_get_modes-for-reuse.patch
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