Problems with two ATI cards, in recent X versions

Michel Dänzer michel at
Fri Aug 24 00:52:05 PDT 2012

On Don, 2012-08-23 at 18:27 -0500, Theodore Kilgore wrote: 
> As you can see, it is intended that the "panning" dimensions ought to 
> remain at 1920x1080 so that by moving the mouse here or there it is 
> possible to see any part of the desktop which is outside of the 800x600 
> window, or, one might say, to be able to move the 800x600 "magnified" 
> window to any part of the 1920x1080 desktop.
> Several X versions ago, this used to work. But then it quit working. What 
> happens instead is that, if the script is run while the mouse cursor is 
> near the bottom right of the screen all is OK. One can move to the left 
> and or move up, and the 800x600 window follows the mouse. But once one has 
> done that, the 800x600 window is frozen in place and cannot be moved back 
> downward, or back to the right.
> Experimentation has caused me to suspect that the problem is in the ATI 
> driver code somewhere, or in the radeon driver code.

That's rather unlikely, as the video driver doesn't deal directly with
mouse input at all but just sets the display viewport as requested by
the X server.

It sounds like this problem could be fixed by this xserver patch:

> Meanwhile, I am forced to run an older version of
> X-practically-everything in order to try to work around this problem. 
> This becomes increasingly difficult, as new versions of various kinds
> of software (the latest Firefox, for example) seem to have
> dependencies on newer versions of X-related libraries.

FWIW, the X server-side components and client-side libraries are mostly
independent, you should be able to use newer versions of the latter with
older versions of the former.

> With this machine, the problem is that it is impossible to stop X once it 
> is started. At worst, the machine can be frozen with a blank screen and an 
> apparent kernel panic, causing the machine to be totally unresponsive to 
> any action except to hit the power button. 

Is it still accessible via network? If so, can you log in via ssh and
get the Xorg.0.log file and dmesg output?

> Unfortunately, I did not keep records of exactly at what point or at which 
> versions of what related packages these problems started to occur with 
> either machine, but I could, of course, report the versions which are 
> known to work and which I am currently using.

It's certainly useful to isolate which version of which package
introduced a problem as much as possible.

Earthling Michel Dänzer           |         
Libre software enthusiast         |          Debian, X and DRI developer

More information about the xorg-driver-ati mailing list