Bug 13408

Summary: Wrong video mode selected?
Product: xorg Reporter: Luca Tettamanti <kronos.it>
Component: Driver/RadeonAssignee: xf86-video-ati maintainers <xorg-driver-ati>
Status: RESOLVED NOTABUG QA Contact: Xorg Project Team <xorg-team>
Severity: normal    
Priority: medium CC: kronos.it
Version: unspecified   
Hardware: Other   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments:
Description Flags
Log of Xorg with radeon driver version 6.7.196
none
Log of Xorg with radeon driver version 6.6.3 none

Description Luca Tettamanti 2007-11-27 10:36:56 UTC 
The new radeon driver selects a video mode that's different from the one used by the stable (i.e. 6.6.3). I reported the issue on the ML for driver version 6.7.192 ; I still see the same behaviour with 6.7.196-1 (Debian/experimental).
To recap, Xorg comes up with a video mode that's slightly different than the one used by the previous driver (6.6.3). The result is that the image is not centered on screen anymore (on the left I see a black stripe of 3-4mm, the right part of the screen is cut).

New mode is:
"1280x1024"   108.00   1280 1328 1440 1688   1024 1025 1028 1066 +hsync +vsync
Old mode is:
"1280x1024"   135.00   1280 1296 1440 1688   1024 1025 1028 1066 +hsync +vsync

The big problem is that Windows also uses the "old" mode, hence I have to adjust monitor settings each time I switch operating system...

I'm attacching the logs for both drivers.
Comment 1 Luca Tettamanti 2007-11-27 10:39:17 UTC 
Created attachment 12745 [details]
Log of Xorg with radeon driver version 6.7.196
Comment 2 Luca Tettamanti 2007-11-27 10:40:07 UTC 
Created attachment 12746 [details]
Log of Xorg with radeon driver version 6.6.3
Comment 3 Luca Tettamanti 2007-12-07 05:15:44 UTC 
Git current (07 Dec 2007) shows the same behaviour.
Comment 4 Alex Deucher 2007-12-08 00:33:47 UTC 
This isn't really a bug per se.  The old driver was just broken :)  IIRC, the old driver used to just add gtf server modes that matched the resolutions of the modes in the edid, while the new driver actually uses the mode from the monitor edid.  If you want to use the old mode, you'll have to specify the old mode as a mode line in the monitor section of your config and set it to the preferred mode or manually pick it with xrandr.  See this page for more info:
http://www.intellinuxgraphics.com/dualhead.html
Make sure you associate the monitor section with the appropriate output.

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