DisplayID support

[Marc Ferland]

On Wed, Oct 13, 2010 at 10:15 AM, Adam Jackson <ajax at nwnk.net> wrote:
> On Wed, 2010-10-13 at 08:59 -0400, Marc Ferland wrote:
>> Hi,
>>
>> I'm currently running Linux on a computer-on-module board from
>> Kontron. I recently upgraded the kernel from 2.6.33.3 to 2.6.35.4 and
>> since that change, Xorg will not detect the LVDS parameters correctly.
>> The LVDS actually uses the DisplayID format
>> (http://en.wikipedia.org/wiki/DisplayID) to expose it's specification.
>>
>> I've bisected this "regression" to commit:
>> 61e57a8d72f2336faf39b5d940215cf085e01e6e in the kernel
>> (http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=61e57a8d72f2336faf39b5d940215cf085e01e6e).
>
> That's... somewhat surprising.  I was under the impression that
> DisplayID lived on a different I2C address than EDID.
>
This board BIOS actually supports both the EDID and DisplayID format.
We chose the DisplayID format because it allowed us to change spread
spectrum option. I guess both must be fetched from the same address in
this case.

>> (EE) intel(0): Unknown EDID version 0
>
> You should be able to find whatever we're getting from the device in
> either dmesg or in /sys/class/drm/*LVDS*/edid.  I'd be interested in
> seeing what your data actually looks like.
>
>> Anyone knows if this has been addressed in a newer Xorg version? Also,
>> is there support in the kernel for the DisplayID format?
>
> I wrote a DisplayID parser for Xorg a while ago, but it's not hooked up
> to anything yet, mostly because I lacked any actual DisplayID devices to
> test it with.  It also has yet to be ported into the kernel, for
> basically the same reason.
>
> So, yeah, show me what you've got, we can make this work.
>
I'm attaching the content of /sys/class/drm/card0-LVDS-1/edid and the
Xorg.0.log file.

I'll be more than happy to provide you with the required information
or test actual patches.

Regards,

Marc
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