[REGRESSION] [KMS] [INTEL] Wrong resolution in console and XWindow

[REGRESSION] [KMS] [INTEL] Wrong resolution in console and XWindow

[Maciej Rutecki]

Last known good: 3.4.4
First bad: 3.5.0

When booting 3.5.0 resolution (in console, and after in KDE) is set to 
1024x768 (60Hz). In 3.4.4 was correct: 1440x900 (60Hz).

Dmesg from 3.5.0:
http://mrutecki.pl/download/kernel/3.5/swinka/dmesg-3.5.0.txt

Dmesg from 3.4.4:
http://mrutecki.pl/download/kernel/3.5/swinka/dmesg-3.4.4.txt

Config 3.5.0:
http://mrutecki.pl/download/kernel/3.5/swinka/config-3.5.0

lspci:
http://mrutecki.pl/download/kernel/3.5/swinka/lspci.txt

Regards
-- 
Maciej Rutecki
http://www.mrutecki.pl

Re: [REGRESSION] [KMS] [INTEL] Wrong resolution in console and XWindow

[Daniel Vetter]

On Wed, Jul 25, 2012 at 10:20:47AM +0200, Maciej Rutecki wrote:
> Last known good: 3.4.4
> First bad: 3.5.0
> 
> When booting 3.5.0 resolution (in console, and after in KDE) is set to 
> 1024x768 (60Hz). In 3.4.4 was correct: 1440x900 (60Hz).

Can you please attach the output of xrandr --verbose for both kernels?
Also, please boot with drm.debug=0xe added to your kernel cmdline and grab
the dmesg (again for both kernels).

Thanks, Daniel

> 
> Dmesg from 3.5.0:
> http://mrutecki.pl/download/kernel/3.5/swinka/dmesg-3.5.0.txt
> 
> Dmesg from 3.4.4:
> http://mrutecki.pl/download/kernel/3.5/swinka/dmesg-3.4.4.txt
> 
> Config 3.5.0:
> http://mrutecki.pl/download/kernel/3.5/swinka/config-3.5.0
> 
> lspci:
> http://mrutecki.pl/download/kernel/3.5/swinka/lspci.txt
> 
> Regards
> -- 
> Maciej Rutecki
> http://www.mrutecki.pl
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48

Re: [REGRESSION] [KMS] [INTEL] Wrong resolution in console and XWindow

[Maciej Rutecki]

On środa, 25 lipca 2012 o 10:29:26 Daniel Vetter wrote:
> On Wed, Jul 25, 2012 at 10:20:47AM +0200, Maciej Rutecki wrote:
> > Last known good: 3.4.4
> > First bad: 3.5.0
> > 
> > When booting 3.5.0 resolution (in console, and after in KDE) is set to
> > 1024x768 (60Hz). In 3.4.4 was correct: 1440x900 (60Hz).
> 
> Can you please attach the output of xrandr --verbose for both kernels?
> Also, please boot with drm.debug=0xe added to your kernel cmdline and grab
> the dmesg (again for both kernels).
> 

Thanks for the ansfer.

Here xrandr and dmesg outputs for 3.4.4 and 3.5.0

http://mrutecki.pl/download/kernel/3.5/swinka/debug/

Regards
-- 
Maciej Rutecki
http://www.mrutecki.pl

Re: [REGRESSION] [KMS] [INTEL] Wrong resolution in console and XWindow

[Daniel Vetter]

On Wed, Jul 25, 2012 at 10:54:25AM +0200, Maciej Rutecki wrote:
> On środa, 25 lipca 2012 o 10:29:26 Daniel Vetter wrote:
> > On Wed, Jul 25, 2012 at 10:20:47AM +0200, Maciej Rutecki wrote:
> > > Last known good: 3.4.4
> > > First bad: 3.5.0
> > > 
> > > When booting 3.5.0 resolution (in console, and after in KDE) is set to
> > > 1024x768 (60Hz). In 3.4.4 was correct: 1440x900 (60Hz).
> > 
> > Can you please attach the output of xrandr --verbose for both kernels?
> > Also, please boot with drm.debug=0xe added to your kernel cmdline and grab
> > the dmesg (again for both kernels).
> > 
> 
> Thanks for the ansfer.
> 
> Here xrandr and dmesg outputs for 3.4.4 and 3.5.0
> 
> http://mrutecki.pl/download/kernel/3.5/swinka/debug/

Can you please test this quick hack:


diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c
index 1991a44..abe1611 100644
--- a/drivers/gpu/drm/i915/intel_i2c.c
+++ b/drivers/gpu/drm/i915/intel_i2c.c
@@ -405,7 +405,7 @@ clear_err:
 	 * timing out seems to happen when there _is_ a ddc chip present, but
 	 * it's slow responding and only answers on the 2nd retry.
 	 */
-	ret = -ENXIO;
+	ret = 0;
 	if (wait_for((I915_READ(GMBUS2 + reg_offset) & GMBUS_ACTIVE) == 0,
 		     10)) {
 		DRM_DEBUG_KMS("GMBUS [%s] timed out after NAK\n",


Thanks, Daniel
-- 
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48

Re: [REGRESSION] [KMS] [INTEL] Wrong resolution in console and XWindow

[Maciej Rutecki]

On środa, 25 lipca 2012 o 11:29:28 Daniel Vetter wrote:
> On Wed, Jul 25, 2012 at 10:54:25AM +0200, Maciej Rutecki wrote:
> > On środa, 25 lipca 2012 o 10:29:26 Daniel Vetter wrote:
> > > On Wed, Jul 25, 2012 at 10:20:47AM +0200, Maciej Rutecki wrote:
> > > > Last known good: 3.4.4
> > > > First bad: 3.5.0
> > > > 
> > > > When booting 3.5.0 resolution (in console, and after in KDE) is set
> > > > to 1024x768 (60Hz). In 3.4.4 was correct: 1440x900 (60Hz).
> > > 
> > > Can you please attach the output of xrandr --verbose for both kernels?
> > > Also, please boot with drm.debug=0xe added to your kernel cmdline and
> > > grab the dmesg (again for both kernels).
> > 
> > Thanks for the ansfer.
> > 
> > Here xrandr and dmesg outputs for 3.4.4 and 3.5.0
> > 
> > http://mrutecki.pl/download/kernel/3.5/swinka/debug/
> 
> Can you please test this quick hack:
> 
> 
> diff --git a/drivers/gpu/drm/i915/intel_i2c.c
> b/drivers/gpu/drm/i915/intel_i2c.c index 1991a44..abe1611 100644
> --- a/drivers/gpu/drm/i915/intel_i2c.c
> +++ b/drivers/gpu/drm/i915/intel_i2c.c
> @@ -405,7 +405,7 @@ clear_err:
>  	 * timing out seems to happen when there _is_ a ddc chip present, but
>  	 * it's slow responding and only answers on the 2nd retry.
>  	 */
> -	ret = -ENXIO;
> +	ret = 0;
>  	if (wait_for((I915_READ(GMBUS2 + reg_offset) & GMBUS_ACTIVE) == 0,
>  		     10)) {
>  		DRM_DEBUG_KMS("GMBUS [%s] timed out after NAK\n",
> 
> 
> Thanks, Daniel

Still the same.

PS. Unfortunately, this afternoon I have small a surgical operation and 
further tests will be possible only after 2-3 days.

Regards
-- 
Maciej Rutecki
http://www.mrutecki.pl

Re: [REGRESSION] [KMS] [INTEL] Wrong resolution in console and XWindow

[Daniel Vetter]

On Wed, Jul 25, 2012 at 12:57 PM, Maciej Rutecki
<maciej.rutecki@gmail.com> wrote:
> On środa, 25 lipca 2012 o 11:29:28 Daniel Vetter wrote:
>> On Wed, Jul 25, 2012 at 10:54:25AM +0200, Maciej Rutecki wrote:
>> > On środa, 25 lipca 2012 o 10:29:26 Daniel Vetter wrote:
>> > > On Wed, Jul 25, 2012 at 10:20:47AM +0200, Maciej Rutecki wrote:
>> > > > Last known good: 3.4.4
>> > > > First bad: 3.5.0
>> > > >
>> > > > When booting 3.5.0 resolution (in console, and after in KDE) is set
>> > > > to 1024x768 (60Hz). In 3.4.4 was correct: 1440x900 (60Hz).
>> > >
>> > > Can you please attach the output of xrandr --verbose for both kernels?
>> > > Also, please boot with drm.debug=0xe added to your kernel cmdline and
>> > > grab the dmesg (again for both kernels).
>> >
>> > Thanks for the ansfer.
>> >
>> > Here xrandr and dmesg outputs for 3.4.4 and 3.5.0
>> >
>> > http://mrutecki.pl/download/kernel/3.5/swinka/debug/
>>
>> Can you please test this quick hack:
>>
>>
>> diff --git a/drivers/gpu/drm/i915/intel_i2c.c
>> b/drivers/gpu/drm/i915/intel_i2c.c index 1991a44..abe1611 100644
>> --- a/drivers/gpu/drm/i915/intel_i2c.c
>> +++ b/drivers/gpu/drm/i915/intel_i2c.c
>> @@ -405,7 +405,7 @@ clear_err:
>>        * timing out seems to happen when there _is_ a ddc chip present, but
>>        * it's slow responding and only answers on the 2nd retry.
>>        */
>> -     ret = -ENXIO;
>> +     ret = 0;
>>       if (wait_for((I915_READ(GMBUS2 + reg_offset) & GMBUS_ACTIVE) == 0,
>>                    10)) {
>>               DRM_DEBUG_KMS("GMBUS [%s] timed out after NAK\n",
>>
>>
>> Thanks, Daniel
>
> Still the same.

Hm, can you attach the dmesg again (with drm.debug=0xe)? If I haven't
botched up something, we should now retry at least the ddc transfer
...
-Daniel

>
> PS. Unfortunately, this afternoon I have small a surgical operation and
> further tests will be possible only after 2-3 days.
>
> Regards
> --
> Maciej Rutecki
> http://www.mrutecki.pl



-- 
Daniel Vetter
daniel.vetter@ffwll.ch - +41 (0) 79 364 57 48 - http://blog.ffwll.ch

Re: [REGRESSION] [KMS] [INTEL] Wrong resolution in console and XWindow

[Daniel Vetter]

On Wed, Jul 25, 2012 at 01:55:59PM +0200, Daniel Vetter wrote:
> On Wed, Jul 25, 2012 at 12:57 PM, Maciej Rutecki
> <maciej.rutecki@gmail.com> wrote:
> > On środa, 25 lipca 2012 o 11:29:28 Daniel Vetter wrote:
> >> On Wed, Jul 25, 2012 at 10:54:25AM +0200, Maciej Rutecki wrote:
> >> > On środa, 25 lipca 2012 o 10:29:26 Daniel Vetter wrote:
> >> > > On Wed, Jul 25, 2012 at 10:20:47AM +0200, Maciej Rutecki wrote:
> >> > > > Last known good: 3.4.4
> >> > > > First bad: 3.5.0
> >> > > >
> >> > > > When booting 3.5.0 resolution (in console, and after in KDE) is set
> >> > > > to 1024x768 (60Hz). In 3.4.4 was correct: 1440x900 (60Hz).
> >> > >
> >> > > Can you please attach the output of xrandr --verbose for both kernels?
> >> > > Also, please boot with drm.debug=0xe added to your kernel cmdline and
> >> > > grab the dmesg (again for both kernels).
> >> >
> >> > Thanks for the ansfer.
> >> >
> >> > Here xrandr and dmesg outputs for 3.4.4 and 3.5.0
> >> >
> >> > http://mrutecki.pl/download/kernel/3.5/swinka/debug/
> >>
> >> Can you please test this quick hack:
> >>
> >>
> >> diff --git a/drivers/gpu/drm/i915/intel_i2c.c
> >> b/drivers/gpu/drm/i915/intel_i2c.c index 1991a44..abe1611 100644
> >> --- a/drivers/gpu/drm/i915/intel_i2c.c
> >> +++ b/drivers/gpu/drm/i915/intel_i2c.c
> >> @@ -405,7 +405,7 @@ clear_err:
> >>        * timing out seems to happen when there _is_ a ddc chip present, but
> >>        * it's slow responding and only answers on the 2nd retry.
> >>        */
> >> -     ret = -ENXIO;
> >> +     ret = 0;
> >>       if (wait_for((I915_READ(GMBUS2 + reg_offset) & GMBUS_ACTIVE) == 0,
> >>                    10)) {
> >>               DRM_DEBUG_KMS("GMBUS [%s] timed out after NAK\n",
> >>
> >>
> >> Thanks, Daniel
> >
> > Still the same.
> 
> Hm, can you attach the dmesg again (with drm.debug=0xe)? If I haven't
> botched up something, we should now retry at least the ddc transfer
> ...

Also, another little snippet for you to test. Fyi I'll be on vacation next
week, so final patch (this one here should really work) might take a notch
longer.

Yours, Daniel
--
diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index bc5e2c9..85eca1c 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -338,6 +338,7 @@ static bool intel_crt_detect_ddc(struct drm_connector *connector)
 	BUG_ON(crt->base.type != INTEL_OUTPUT_ANALOG);
 
 	i2c = intel_gmbus_get_adapter(dev_priv, dev_priv->crt_ddc_pin);
+	intel_gmbus_force_bit(i2c, true);
 	edid = drm_get_edid(connector, i2c);
 
 	if (edid) {
@@ -546,12 +547,14 @@ static int intel_crt_get_modes(struct drm_connector *connector)
 	struct i2c_adapter *i2c;
 
 	i2c = intel_gmbus_get_adapter(dev_priv, dev_priv->crt_ddc_pin);
+	intel_gmbus_force_bit(i2c, true);
 	ret = intel_ddc_get_modes(connector, i2c);
 	if (ret || !IS_G4X(dev))
 		return ret;
 
 	/* Try to probe digital port for output in DVI-I -> VGA mode. */
 	i2c = intel_gmbus_get_adapter(dev_priv, GMBUS_PORT_DPB);
+	intel_gmbus_force_bit(i2c, true);
 	return intel_ddc_get_modes(connector, i2c);
 }
-- 
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48

Re: [REGRESSION] [KMS] [INTEL] Wrong resolution in console and XWindow

[Maciej Rutecki]

On czwartek, 26 lipca 2012 o 14:38:28 Daniel Vetter wrote:
> On Wed, Jul 25, 2012 at 01:55:59PM +0200, Daniel Vetter wrote:
> > On Wed, Jul 25, 2012 at 12:57 PM, Maciej Rutecki
> > 
> > <maciej.rutecki@gmail.com> wrote:
> > > On środa, 25 lipca 2012 o 11:29:28 Daniel Vetter wrote:
> > >> On Wed, Jul 25, 2012 at 10:54:25AM +0200, Maciej Rutecki wrote:
> > >> > On środa, 25 lipca 2012 o 10:29:26 Daniel Vetter wrote:
> > >> > > On Wed, Jul 25, 2012 at 10:20:47AM +0200, Maciej Rutecki wrote:
> > >> > > > Last known good: 3.4.4
> > >> > > > First bad: 3.5.0
> > >> > > > 
> > >> > > > When booting 3.5.0 resolution (in console, and after in KDE) is
> > >> > > > set to 1024x768 (60Hz). In 3.4.4 was correct: 1440x900 (60Hz).
> > >> > > 
> > >> > > Can you please attach the output of xrandr --verbose for both
> > >> > > kernels? Also, please boot with drm.debug=0xe added to your
> > >> > > kernel cmdline and grab the dmesg (again for both kernels).
> > >> > 
> > >> > Thanks for the ansfer.
> > >> > 
> > >> > Here xrandr and dmesg outputs for 3.4.4 and 3.5.0
> > >> > 
> > >> > http://mrutecki.pl/download/kernel/3.5/swinka/debug/
> > >> 
> > >> Can you please test this quick hack:
> > >> 
> > >> 
> > >> diff --git a/drivers/gpu/drm/i915/intel_i2c.c
> > >> b/drivers/gpu/drm/i915/intel_i2c.c index 1991a44..abe1611 100644
> > >> --- a/drivers/gpu/drm/i915/intel_i2c.c
> > >> +++ b/drivers/gpu/drm/i915/intel_i2c.c
> > >> 
> > >> @@ -405,7 +405,7 @@ clear_err:
> > >>        * timing out seems to happen when there _is_ a ddc chip
> > >>        present, but * it's slow responding and only answers on the
> > >>        2nd retry. */
> > >> 
> > >> -     ret = -ENXIO;
> > >> +     ret = 0;
> > >> 
> > >>       if (wait_for((I915_READ(GMBUS2 + reg_offset) & GMBUS_ACTIVE) ==
> > >>       0,
> > >>       
> > >>                    10)) {
> > >>               
> > >>               DRM_DEBUG_KMS("GMBUS [%s] timed out after NAK\n",
> > >> 
> > >> Thanks, Daniel
> > > 
> > > Still the same.
> > 
> > Hm, can you attach the dmesg again (with drm.debug=0xe)? If I haven't
> > botched up something, we should now retry at least the ddc transfer
> > ...
> 
> Also, another little snippet for you to test. Fyi I'll be on vacation next
> week, so final patch (this one here should really work) might take a notch
> longer.
> 
> Yours, Daniel
> --
> diff --git a/drivers/gpu/drm/i915/intel_crt.c
> b/drivers/gpu/drm/i915/intel_crt.c index bc5e2c9..85eca1c 100644
> --- a/drivers/gpu/drm/i915/intel_crt.c
> +++ b/drivers/gpu/drm/i915/intel_crt.c
> @@ -338,6 +338,7 @@ static bool intel_crt_detect_ddc(struct drm_connector
> *connector) BUG_ON(crt->base.type != INTEL_OUTPUT_ANALOG);
> 
>  	i2c = intel_gmbus_get_adapter(dev_priv, dev_priv->crt_ddc_pin);
> +	intel_gmbus_force_bit(i2c, true);
>  	edid = drm_get_edid(connector, i2c);
> 
>  	if (edid) {
> @@ -546,12 +547,14 @@ static int intel_crt_get_modes(struct drm_connector
> *connector) struct i2c_adapter *i2c;
> 
>  	i2c = intel_gmbus_get_adapter(dev_priv, dev_priv->crt_ddc_pin);
> +	intel_gmbus_force_bit(i2c, true);
>  	ret = intel_ddc_get_modes(connector, i2c);
>  	if (ret || !IS_G4X(dev))
>  		return ret;
> 
>  	/* Try to probe digital port for output in DVI-I -> VGA mode. */
>  	i2c = intel_gmbus_get_adapter(dev_priv, GMBUS_PORT_DPB);
> +	intel_gmbus_force_bit(i2c, true);
>  	return intel_ddc_get_modes(connector, i2c);
>  }

I have little problem with the patch:
$ patch -p1 < /tmp/latka.patch 
patching file drivers/gpu/drm/i915/intel_crt.c
Hunk #1 FAILED at 338.
patch unexpectedly ends in middle of line
Hunk #2 succeeded at 498 with fuzz 2 (offset -48 lines).
1 out of 2 hunks FAILED -- saving rejects to file 
drivers/gpu/drm/i915/intel_crt.c.rej

But I add "intel_gmbus_force_bit(i2c, true);" manually and now resolution is 
OK. Thanks for help.

PS. I also will be in vacation between 4-19 August, so my test may take 
longer.

Regards
-- 
Maciej Rutecki
http://www.mrutecki.pl

[PATCH 0/2] GMBUS EDID read bit-banging fallback

[Jani Nikula]

Alex, Maciej, please test the following to see if it fixes the issue
[1], thanks.

BR,
Jani.


[1] https://bugzilla.kernel.org/show_bug.cgi?id=45881

Jani Nikula (2):
  drm/i915: extract connector update from intel_ddc_get_modes() for
    reuse
  drm/i915: fall back to bit-banging if GMBUS fails in CRT EDID reads

 drivers/gpu/drm/i915/intel_crt.c   |   36 +++++++++++++++++++++++++++++++++---
 drivers/gpu/drm/i915/intel_drv.h   |    2 ++
 drivers/gpu/drm/i915/intel_modes.c |   31 ++++++++++++++++++++++---------
 3 files changed, 57 insertions(+), 12 deletions(-)

-- 
1.7.9.5

[PATCH 1/2] drm/i915: extract connector update from intel_ddc_get_modes() for reuse

[Jani Nikula]

Refactor the connector update part of intel_ddc_get_modes() into a separate
intel_connector_update_modes() function for reuse. No functional changes.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/i915/intel_drv.h   |    2 ++
 drivers/gpu/drm/i915/intel_modes.c |   31 ++++++++++++++++++++++---------
 2 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 13f0467..8a224ca 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -357,6 +357,8 @@ struct intel_fbc_work {
 	int interval;
 };
 
+int intel_connector_update_modes(struct drm_connector *connector,
+				struct edid *edid);
 int intel_ddc_get_modes(struct drm_connector *c, struct i2c_adapter *adapter);
 
 extern void intel_attach_force_audio_property(struct drm_connector *connector);
diff --git a/drivers/gpu/drm/i915/intel_modes.c b/drivers/gpu/drm/i915/intel_modes.c
index 45848b9..29b7259 100644
--- a/drivers/gpu/drm/i915/intel_modes.c
+++ b/drivers/gpu/drm/i915/intel_modes.c
@@ -33,6 +33,25 @@
 #include "i915_drv.h"
 
 /**
+ * intel_connector_update_modes - update connector from edid
+ * @connector: DRM connector device to use
+ * @edid: previously read EDID information
+ */
+int intel_connector_update_modes(struct drm_connector *connector,
+				struct edid *edid)
+{
+	int ret;
+
+	drm_mode_connector_update_edid_property(connector, edid);
+	ret = drm_add_edid_modes(connector, edid);
+	drm_edid_to_eld(connector, edid);
+	connector->display_info.raw_edid = NULL;
+	kfree(edid);
+
+	return ret;
+}
+
+/**
  * intel_ddc_get_modes - get modelist from monitor
  * @connector: DRM connector device to use
  * @adapter: i2c adapter
@@ -43,18 +62,12 @@ int intel_ddc_get_modes(struct drm_connector *connector,
 			struct i2c_adapter *adapter)
 {
 	struct edid *edid;
-	int ret = 0;
 
 	edid = drm_get_edid(connector, adapter);
-	if (edid) {
-		drm_mode_connector_update_edid_property(connector, edid);
-		ret = drm_add_edid_modes(connector, edid);
-		drm_edid_to_eld(connector, edid);
-		connector->display_info.raw_edid = NULL;
-		kfree(edid);
-	}
+	if (!edid)
+		return 0;
 
-	return ret;
+	return intel_connector_update_modes(connector, edid);
 }
 
 static const struct drm_prop_enum_list force_audio_names[] = {
-- 
1.7.9.5

[PATCH 2/2] drm/i915: fall back to bit-banging if GMBUS fails in CRT EDID reads

[Jani Nikula]

GMBUS was enabled over bit-banging as the default in commits:

commit c3dfefa0a6d235bd465309e12f4c56ea16e71111
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Tue Feb 14 22:37:25 2012 +0100

    drm/i915: reenable gmbus on gen3+ again

and

commit 0fb3f969c8683505fb7323c06bf8a999a5a45a15
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
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: <201207251020.47637.maciej.rutecki@gmail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=45881
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/i915/intel_crt.c |   36 +++++++++++++++++++++++++++++++++---
 1 file changed, 33 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index bc5e2c9..80bf311 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -328,6 +328,36 @@ static bool intel_crt_detect_hotplug(struct drm_connector *connector)
 	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);
@@ -338,7 +368,7 @@ static bool intel_crt_detect_ddc(struct drm_connector *connector)
 	BUG_ON(crt->base.type != INTEL_OUTPUT_ANALOG);
 
 	i2c = intel_gmbus_get_adapter(dev_priv, dev_priv->crt_ddc_pin);
-	edid = drm_get_edid(connector, i2c);
+	edid = intel_crt_get_edid(connector, i2c);
 
 	if (edid) {
 		bool is_digital = edid->input & DRM_EDID_INPUT_DIGITAL;
@@ -546,13 +576,13 @@ static int intel_crt_get_modes(struct drm_connector *connector)
 	struct i2c_adapter *i2c;
 
 	i2c = intel_gmbus_get_adapter(dev_priv, dev_priv->crt_ddc_pin);
-	ret = intel_ddc_get_modes(connector, i2c);
+	ret = intel_crt_ddc_get_modes(connector, i2c);
 	if (ret || !IS_G4X(dev))
 		return ret;
 
 	/* Try to probe digital port for output in DVI-I -> VGA mode. */
 	i2c = intel_gmbus_get_adapter(dev_priv, GMBUS_PORT_DPB);
-	return intel_ddc_get_modes(connector, i2c);
+	return intel_crt_ddc_get_modes(connector, i2c);
 }
 
 static int intel_crt_set_property(struct drm_connector *connector,
-- 
1.7.9.5

Re: [PATCH 2/2] drm/i915: fall back to bit-banging if GMBUS fails in CRT EDID reads

[Daniel Vetter]

On Mon, Aug 13, 2012 at 01:22:35PM +0300, Jani Nikula wrote:
> GMBUS was enabled over bit-banging as the default in commits:
> 
> commit c3dfefa0a6d235bd465309e12f4c56ea16e71111
> Author: Daniel Vetter <daniel.vetter@ffwll.ch>
> Date:   Tue Feb 14 22:37:25 2012 +0100
> 
>     drm/i915: reenable gmbus on gen3+ again
> 
> and
> 
> commit 0fb3f969c8683505fb7323c06bf8a999a5a45a15
> Author: Daniel Vetter <daniel.vetter@ffwll.ch>
> 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: <201207251020.47637.maciej.rutecki@gmail.com>
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=45881
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Patches applied to -fixes with the tested-by result from the bug report.
I've also put a cc: stable on both of them, since the regression is
already in 3.4.

Thanks, Daniel
-- 
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48