Monitor with corrupted EDID

Monitor with corrupted EDID

[Flavio Castelli]

For an unknown reason both my monitors ended up with a corrupted EDID.
They both provide VGA and DVI input. The VGA input works fine, while
DVI is broken because of the EDID issue.

Using these [1] instructions I have been able to read the EDID and fix
it. Unfortunately I'm not able to write it back to the eeprom.
I always get this message:
  i2c i2c-1: sendbytes: NAK bailout.

This is what I usually see in /var/log/message
[dump of the EDID]
nouveau 0000:01:00.0: DVI-D-1: EDID block 0 invalid.
[drm] nouveau 0000:01:00.0: DDC responded, but no EDID for DVI-D-1

Do you know why writing to the monitor does not work? I suspect the
eeprom is write protected

Googling a bit I noticed the nvidia driver allows to ignore the EDID
returned by the monitor and use a custom one. I looks like the nouveau
drivers do not offer this feature. Am I wrong?

These are my specs:
  * kernel: 3.4.11-2.16-desktop
  * architecture: x86_64
  * distribution: openSUSE 12.2
  * xorg-x11-driver-video-nouveau-0.0.16_20120321_ab7291d-3.5.1.x86_64
  * X.Org X Server 1.12.3
  * NVIDIA Corporation G84M [Quadro FX 570M]
  * Monitor 1: lenovo l220x wide
  * Monitor 2: lenovo l2440p


What should I do?

Thanks in advance
Flavio

Re: Monitor with corrupted EDID

[Marcin Slusarz]

On Thu, Feb 07, 2013 at 04:16:54PM +0100, Flavio Castelli wrote:
> For an unknown reason both my monitors ended up with a corrupted EDID.
> They both provide VGA and DVI input. The VGA input works fine, while
> DVI is broken because of the EDID issue.
> 
> Using these [1] instructions I have been able to read the EDID and fix
> it. Unfortunately I'm not able to write it back to the eeprom.
> I always get this message:
>   i2c i2c-1: sendbytes: NAK bailout.
> 
> This is what I usually see in /var/log/message
> [dump of the EDID]
> nouveau 0000:01:00.0: DVI-D-1: EDID block 0 invalid.
> [drm] nouveau 0000:01:00.0: DDC responded, but no EDID for DVI-D-1
> 
> Do you know why writing to the monitor does not work? I suspect the
> eeprom is write protected
> 
> Googling a bit I noticed the nvidia driver allows to ignore the EDID
> returned by the monitor and use a custom one. I looks like the nouveau
> drivers do not offer this feature. Am I wrong?

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=blob;f=Documentation/EDID/HOWTO.txt

> 
> These are my specs:
>   * kernel: 3.4.11-2.16-desktop
>   * architecture: x86_64
>   * distribution: openSUSE 12.2
>   * xorg-x11-driver-video-nouveau-0.0.16_20120321_ab7291d-3.5.1.x86_64
>   * X.Org X Server 1.12.3
>   * NVIDIA Corporation G84M [Quadro FX 570M]
>   * Monitor 1: lenovo l220x wide
>   * Monitor 2: lenovo l2440p
> 
> 
> What should I do?
> 
> Thanks in advance
> Flavio

Re: Monitor with corrupted EDID

[mwesten]

On 02/07/2013 10:16 AM, Flavio Castelli wrote:
> For an unknown reason both my monitors ended up with a corrupted EDID.
> They both provide VGA and DVI input. The VGA input works fine, while
> DVI is broken because of the EDID issue.
>
> Using these [1] instructions I have been able to read the EDID and fix
> it. Unfortunately I'm not able to write it back to the eeprom.
> I always get this message:
>    i2c i2c-1: sendbytes: NAK bailout.
>
> This is what I usually see in /var/log/message
> [dump of the EDID]
> nouveau 0000:01:00.0: DVI-D-1: EDID block 0 invalid.
> [drm] nouveau 0000:01:00.0: DDC responded, but no EDID for DVI-D-1
>
> Do you know why writing to the monitor does not work? I suspect the
> eeprom is write protected
>
> Googling a bit I noticed the nvidia driver allows to ignore the EDID
> returned by the monitor and use a custom one. I looks like the nouveau
> drivers do not offer this feature. Am I wrong?
>
> These are my specs:
>    * kernel: 3.4.11-2.16-desktop
>    * architecture: x86_64
>    * distribution: openSUSE 12.2
>    * xorg-x11-driver-video-nouveau-0.0.16_20120321_ab7291d-3.5.1.x86_64
>    * X.Org X Server 1.12.3
>    * NVIDIA Corporation G84M [Quadro FX 570M]
>    * Monitor 1: lenovo l220x wide
>    * Monitor 2: lenovo l2440p
>
>
> What should I do?
>
> Thanks in advance
> Flavio
> _______________________________________________
> Nouveau mailing list
> Nouveau-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org
> http://lists.freedesktop.org/mailman/listinfo/nouveau
>

I recently used a DOS program called ddcw.exe to fix the corrupted EDID 
on one of my monitors.

See this site, http://byuu.org/articles/computing/edid
and get it here, http://www.komeil.com/download/2984

If that doesn't work, the drm_kms_helper module in newer kernels should 
have a parameter to get around the problem.

See https://www.osadl.org/Single-View.111+M50eaf2f2c66.0.html

-Mike

Re: Monitor with corrupted EDID

[Flavio Castelli]

On 02/07/2013 08:37 PM, mwesten wrote:
> I recently used a DOS program called ddcw.exe to fix the corrupted EDID
> on one of my monitors.

I already tried to write the good EDID into the monitor but I failed. I 
also tried to do that using i2cset with the same result. I suspect the 
EEPROM is write protected...

I'll give a shot to this program.

> If that doesn't work, the drm_kms_helper module in newer kernels should
> have a parameter to get around the problem.
>
> See https://www.osadl.org/Single-View.111+M50eaf2f2c66.0.html

That's working!

My monitor now is powered and I can use it.

There's only one minor issue: the nouveau module keeps complaining about 
the wrong EDID received by this monitor. Is there a way to tell the 
driver to stop probing the monitor?

Thanks a lot for the help

Flavio

Re: Monitor with corrupted EDID

[mwesten]

On 02/08/2013 03:23 AM, Flavio Castelli wrote:
> On 02/07/2013 08:37 PM, mwesten wrote:
>> I recently used a DOS program called ddcw.exe to fix the corrupted EDID
>> on one of my monitors.
>
> I already tried to write the good EDID into the monitor but I failed. I
> also tried to do that using i2cset with the same result. I suspect the
> EEPROM is write protected...
>
> I'll give a shot to this program.

My suspicion is that if the EDID data got corrupted in the first place, 
then it's not protected.  I don't know about i2cset, or any other methods.

>> If that doesn't work, the drm_kms_helper module in newer kernels should
>> have a parameter to get around the problem.
>>
>> See https://www.osadl.org/Single-View.111+M50eaf2f2c66.0.html
>
> That's working!
>
> My monitor now is powered and I can use it.
>
> There's only one minor issue: the nouveau module keeps complaining about
> the wrong EDID received by this monitor. Is there a way to tell the
> driver to stop probing the monitor?

I've noticed that too, and I'm not aware of a way to prevent it.

> Thanks a lot for the help

No problem.

-Mike

Re: Monitor with corrupted EDID

[Flavio Castelli]

On 02/08/2013 11:44 AM, mwesten wrote:
> My suspicion is that if the EDID data got corrupted in the first place,
> then it's not protected.  I don't know about i2cset, or any other methods.

That's exactly what I'm thinking. I'm trying to overwrite the EEPROM 
using a DVI cable (since it's the DVI EDID which is broken). I saw other 
people used a vga -> dvi cable to do that because some pins could not be 
"exposed" by the DVI cable. I'm don't fully believe in this explanation.

Cheers
Flavio

Re: Monitor with corrupted EDID

[Dave Airlie]

>>
>> My suspicion is that if the EDID data got corrupted in the first place,
>> then it's not protected.  I don't know about i2cset, or any other methods.
>
>
> That's exactly what I'm thinking. I'm trying to overwrite the EEPROM using a
> DVI cable (since it's the DVI EDID which is broken). I saw other people used
> a vga -> dvi cable to do that because some pins could not be "exposed" by
> the DVI cable. I'm don't fully believe in this explanation.

I've found with some monitors, that unplugging everything, power, and
all monitor cables, and leaving it for a few minutes, then plugging it
all back in, can sometimes restore the EDID. Some EDID chips stop a
copy in RAM that gets powered from both mains and the ddc lines, so
you really need to disconnect everything.

(though I'm not sure how common this configuration is in monitors).

Dave.