xorg.conf PreferredMode resolution ignored in ATI video driver

[Alex Deucher]

On Mon, Jun 23, 2008 at 11:14 AM, Don Waugaman <dpw at cs.arizona.edu> wrote:
> Greetings,
>
> I have an asymmetric dualhead setup - 1920x1200 LCD on the left,
> 1600x1200 CRT on the right - and I'm trying to get a static xorg.conf
> setup working without resorting to xrandr every time I log in.  (Getting
> the screen resolution to native on the LCD monitor under GDM would be a
> plus.)
>
> I'm using Fedora 9 with xorg-x11-drv-ati-6.8.0-14 on an ATI 9550-based
> card, by the way.
>
> Upon X startup, the LCD sets itself to 1600x1200:
>
> Screen 0: minimum 320 x 200, current 3520 x 1200, maximum 3520 x 1200
> VGA-0 connected 1600x1200+1600+0 (normal left inverted right x axis y
> axis) 0mm x 0mm
>   1600x1200 at 75Hz   75.0*+
>   1360x768       59.8
>   1152x864       60.0
>   1024x768       60.0
>   800x600        60.3
>   640x480        59.9
> DVI-0 connected 1600x1200+0+0 (normal left inverted right x axis y axis)
> 518mm x 324mm
>   1920x1200      60.0 +   60.0
>   1600x1200      60.0*    60.0
>   1680x1050      60.0
>   1600x1024      60.2
>   1400x1050      74.8     70.0     60.0
>   1280x1024      75.0     60.0     60.0
>   1440x900       59.9
>   1280x960       60.0     60.0
>   1360x768       59.8
>   1152x864       75.0     75.0     75.0     70.0     60.0
>   1024x768       75.1     75.0     70.1     60.0
>   832x624        74.6
>   800x600        72.2     75.0     60.3     56.2
>   640x480        75.0     72.8     72.8     75.0     66.7     60.0
> 59.9
>   720x400        70.1
> S-video disconnected (normal left inverted right x axis y axis)
>
> I can change it to use 1920x1200, and also rebase the VGA to the
> screen's right to eliminate the overlap, but I'd prefer to not have to
> do this every time I log in.
>
> I noticed the following lines in my Xorg.0.log:
>
> (II) RADEON(0): Using user preference for initial modes
> (II) RADEON(0): Output VGA-0 using initial mode 1600x1200 at 75Hz
> (II) RADEON(0): Output DVI-0 using initial mode 1600x1200
>
> which seems odd since my preference in the file is for the 1920x1200
> mode.  Is there a bug in the X server preventing this from being
> selected somehow?  Is it selecting a mode to match the CRT head?
>
> Also, periodically the X server's CPU utilization goes through the roof,
> and interactivity pauses briefly.  After about 3-5 seconds, it picks
> back up again.  These pauses are annoying, and they really interfere
> with the work cycle - is there a way to figure out why this is happening
> and what can be done about it?
>
> If there is a better forum for asking these kinds of questions, feel
> free to direct me to it.
>
> I'm attaching my current xorg.conf, I can send the server log as well if
> it would help, but it's rather larger and I'd hate to take up so much
> bandwidth.

Wht xserver are you using.  I think this has been fixed in git master
and the 1.5rc releases.

Alex