Bug#613670: linux-image-2.6.32-bpo.5-686: EDID checksum failure kills X while switched away using KVM switch
On Tue, Aug 30, 2011 at 01:43:15 -0500, Jonathan Nieder wrote:
> Hi Conrad,
>
> Conrad Hughes wrote:
>
> > I'm using a keyboard-video-mouse (KVM) switch to switch between a number
> > of computers; before squeeze, this worked brilliantly. Since upgrading
> > to squeeze, a few minutes after I switch to another computer, my squeeze
> > install kills X completely. All I'm seeing is the following in
> > /var/log/syslog:
> [...]
> > [drm:edid_is_valid] *ERROR* EDID checksum is invalid, remainder is 130
> > [drm:edid_is_valid] *ERROR* Raw EDID:
> > <3>00 ff ff ff ff ff ff 00 ff ff ff ff ff ff ff ff
> > <3>ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
> [...]
> > A similar problem has turned up in Microsoft Windows 7, where continuous
> > checking of EDID results in the OS switching to default monitor
> > resolution after the user switches away (or even turns off their monitor
> > in some cases). Microsoft apparently blame this on obsolete KVM
> > hardware and AFAICS have not offered a facility to disable the
> > continuous checking; I hope there might be a means of disabling the
> > check in Debian though
>
> Thanks for reporting it, and sorry for the slow response. I wonder if
> the change v2.6.35-rc1~18^2~2 (drm/edid: Allow non-fatal checksum
> errors in CEA blocks, 2010-05-25[1]) would help here.
>
That seems unlikely, the error above suggests the EDID is pretty much
all ones in the main block, not just in CEA extension blocks.
Cheers,
Julien
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