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

[Michel Dänzer]

On Don, 2012-07-19 at 23:43 +1000, James Robertson wrote: 
> Package: xserver-xorg-video-ati
> Version: 1:6.14.4-5
> Severity: normal
> 
> Dear Maintainer,
> 
> I have a Lenovo R500 laptop with an "[AMD] nee ATI RV620 [Mobility Radeon HD 3400
> Series]" graphics chip
> 
> I recently obtained 2x AOC monitors with a 1920x1080 resolution and have
> these connected via DVI and VGA to a laptop docking station.
> 
> The laptop only supports a maximum of 2 displays at once.
> 
> With the laptop display disabled I get screen tearing and corruption when
> using 1 or both of the external monitors with 1920x1080 resolution.
> But strangely if I set one of them to a lower resolution such as 1680x1050
> (the other still at 1920x1080) the screen tearing issue dissapears.  Odd given
> a single display gets the tearing...
> 
> If using the laptop's display in conjunction with either DVI or VGA
> connected monitor at 1920x1080 I experience no tearing.
> 
> If I disable EXAPixmaps the problem is fixed [...]

Can you elaborate on what exactly 'tearing and corruption' means?

Does booting with radeon.disp_priority=2 on the kernel command line
help?

Please provide the output of xrandr --verbose for each case.


-- 
Earthling Michel Dänzer           |                   http://www.amd.com
Libre software enthusiast         |          Debian, X and DRI developer