Bug#682099: xserver-xorg-video-ati: EXAPixmaps=On screen tearing at high resolution under certain configurations

[James Robertson]

On 22 July 2012 13:20, James Robertson <j at mesrobertson.com> wrote:
> On 21 July 2012 03:45, Michel Dänzer <daenzer at debian.org> wrote:
>>
>> Can you elaborate on what exactly 'tearing and corruption' means?
>
> I have created a brief video to show the tearing.  It occurs when
> basically any input occurs such as typing, moving the mouse and as per
> the video moving windows.
>
> https://docs.google.com/open?id=0B2vLcjUrgXL-aUdWekU0dE9qbHM
>
>> Does booting with radeon.disp_priority=2 on the kernel command line
>> help?
>
> No
>
>> Please provide the output of xrandr --verbose for each case
>
> Please see attached txt file.
>
> On 21 July 2012 04:33, Alex Deucher <alexdeucher at gmail.com> wrote:
>> Also note that rendering can only be synchronized to one head at a
>> time to avoid tearing.  If you have windows that span multiple heads,
>> you may get tearing on the non-synced heads.
>
> I don't fully understand the technical side of what you have described
> but wouldn't this mean tearing should only occur when using multiple
> monitors?  I get tearing on DVI-0 or VGA-0 standalone.
>
> I would also note that the tearing is worse when using both DVI-0 and
> VGA-0 together.  I also physically removed DVI-0 and visa versa for
> VGA-0 and still had the problem.
>
> Thanks

Whilst watching a flash video in Chromium this evening, I scrolled
down the web page and noticed the tearing even when I had "EXAPixmaps"
"off".  The tearing was not as severe, but nonetheless occurred.

As a quick test I tried setting the VGA-0 Display to 1680x1050 (DVI-0
still at 1920x1080) and it was fine.  Using just DVI-0 standalone
@1920x1080 also had tearing.

Thanks