linux-kernel - Re: Intel graphics drm issue?

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Date:	Sun, 14 Oct 2012 14:03:21 -0400
From:	Mark Hounschell <dmarkh@....rr.com>
To:	Bruno Prémont <bonbons@...ux-vserver.org>
CC:	markh@...pro.net, linux-kernel@...r.kernel.org,
	Intel Graphics Development <intel-gfx@...ts.freedesktop.org>
Subject: Re: Intel graphics drm issue?

On 10/14/2012 01:22 PM, Bruno Prémont wrote:
> Hi Mark,
>
> On Sun, 14 October 2012 Mark Hounschell <dmarkh@....rr.com> wrote:
>> I've taken the EDID data from that service manual. I've looked at the
>> EDID-Howto for how to specify the connector but all I see is:
>>
>> "An EDID data set will only be used for a particular connector,
>>    if its name and a colon are prepended to the EDID name."
>>
>> Where can I find the connector names?
>
> Those are the ones you see under /sys/class/drm/, without the card0-
> prefix.
>
> E.g. on my system I have:
>
> # ls /sys/class/drm/
> card0  card0-DVI-I-1  card0-LVDS-1  card0-VGA-1  controlD64  version
>
> Thus I have connectors "DVI-I-1", "LVDS-1" and "VGA-1" (note that your
> HDMI connector might not be named HDMI-1, if you are not sure which one
> it is, you can look at the files below (edid, enabled, status) which
> should help your find the right connector).
>

Perfect.

>
> In addition, if you rmmod i915 and modprobe it again connectors will get
> increased suffix numbers. So don't expect them to remain the same if you
> have multiple GPUs detected in random order or if you rebind them to
> their driver. (though except during testing or for special systems you
> don't have to worry about this)
>
>> And could I ask if this simple pgm might work to build the file I need?
>
> It looks fine. You can also check the output with hexdump just to
> make sure it looks sane.

Did that and the data looks swapped compared to the array written, but I 
guess that's normal?

> If it's broken kernel will tell you that checksum does not match.
>

So the  check sum is actually already in the data provided by the service 
manual then.

> In any case the (successful) loading of edid should be visible in kernel
> log.
>

I'll be trying this a little later in the day.

Thanks again
Mark


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