Bug#595033: xserver-xorg-video-ati: Only one display works at a time with RV620 [FirePro 2260] with two DisplayPort output

[Alex Deucher]

On Tue, Aug 31, 2010 at 10:59 AM, Thomas PIERSON <web.pierson at gmail.com> wrote:
> Package: xserver-xorg-video-ati
> Version: 1:6.13.1-2
> Severity: normal
>
> Hi,
>
> I have an issue with 2 monitors connected on two DislpayPort output. The card
> is an ATI "FirePro 2260". And only one display can works at a time.
> $ lspci | grep VGA
> 02:00.0 VGA compatible controller: ATI Technologies Inc RV620 [FirePro 2260]
>
> My issue looks like this archived bug : http://bugs.debian.org/cgi-
> bin/bugreport.cgi?bug=569970
>> The symptoms are that only one display can be driven at a time.
> It also talk about two DisplayPort connections.
>
> So, the 2 monitor are connected and activated in clone mode :
>
> $ xrandr
> Screen 0: minimum 320 x 200, current 1280 x 1024, maximum 8192 x 8192
> DisplayPort-0 connected 1280x1024+0+0 (normal left inverted right x axis y
> axis) 408mm x 255mm
>   1680x1050      60.0 +
>   1600x1200      60.0
>   1400x1050      60.0
>   1280x1024      75.0     60.0*
>   1440x900       59.9
>   1280x960       60.0
>   1152x864       75.0
>   1024x768       75.1     70.1     60.0
>   832x624        74.6
>   800x600        72.2     75.0     60.3     56.2
>   640x480        72.8     75.0     66.7     60.0
>   720x400        70.1
>   640x400        70.0
> DisplayPort-1 connected 1280x1024+0+0 (normal left inverted right x axis y
> axis) 380mm x 305mm
>   1280x1024      60.0*+   75.0
>   1152x864       75.0
>   1024x768       75.1     60.0
>   800x600        75.0     60.3
>   640x480        75.0     60.0
>   720x400        70.1
>
> But only one display works.
> After that if I run for example :
> xrandr --output DisplayPort-0 --left-of DisplayPort-1
> I have a black screen on the 2 monitors and I can't access to a terminal.
>
> I noticed something else : When I turn off and on again the second monitor
> (manually) an kernel error occurred :
> [18515.140220] [drm:radeon_process_aux_ch] *ERROR* Buffer to small for return
> answer 1 6
> During some seconds, the main monitor get stranges color and lights intensity!
>
> It seem to be the same problem that the bug #569970 but I am not sure.
> Someone have an idea to solve this?
> Tell me if you need other logs or informations.

You need this patch most likely:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=5137ee940c3e593ae5578a7a12a604eb8f239ac0
which means 2.6.36rc3 or newer.

Alex

>
> Regards,
> Thomas PIERSON
>
>
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>
>