[Xorg-driver-geode] 1024x600px panel support on Geode LX-800

[Dawid Nogens]

Hello,

I'm trying to get a Geode LX-800 based panel PC running with xorg. The panel 
PC is equipped with a 1024x600 flat screen that is connected to an onboard TFT 
panel connector.
Unfortunatly the README to the xserver-xorg-video-geode driver tells WXGA 
resolutions only can be used when TFT support is disabled in the BIOS.

I've currently installed Ubuntu Netbook Remix based on Ubuntu 9.04 jaunty.
 - Kernel 2.6.28.11. Custom kernel, based on standard generic x86 kernel, but 
disabled EDID-support. 
 - xorg 1.6.3-1ubuntu6
 - xserver-xorg-video-geode 2.11.4 compiled for 1.6.3
In the BIOS the flat panel is configured with a resolution of 1024x600 @ 60Hz.

The situation is as follows:
To get Linux running on the panel PC, it had to be installed using another 
system and then a custom kernel with disabled EDID support had to be compiled. 
The system comes up with a resolution of 1024x768 which perfectly fits the 
physical resolution of the screen, but with an area of 168 px missing at the 
bottom.

Manually adding a 1024x600 mode using xrandr and configuring xorg to use that 
resolution results in a virtual desktop of 1024x600 px which is scaled up to 
fit a 1024x768 screen. So again, an area at the bottom of the virtual screen is 
missing and this time the resolution doesn't fit the screens physical 
resolution.

Playing around with the "gnome display preferences" i stumbled about 
something. Starting up xorg with a resolution of 1024x600 (which in fact is 
scaled up to 1024x768) and then using "gnome display preferences" to change 
the resolution to 1024x768 had the following effect: 
First the resolution is changed to 1024x768, but the virtual desktop's size 
remains 1024x600. That state is displaying exactly what I want. The display's 
resolution fits the physical resolution of the screen and the virtual desktop 
fits the area the screen is able to show. After that, "gnome display 
preferences" detects that the resolution used is bigger than the virtual 
desktop and adjusts the virtual desktop to the selected resolution of 
1024x768. 

Now to the questions I have:
- Is it possible to add support for a WSVGA display that is connected to the 
onboard TFT interface to the driver? 
- What is needed to do that? Is it just enough to add the appropriate mode for 
1024x600 to lx_panel_modes[] in "lx_panel.c", or does it demand extensive 
changes?

- If there isn't any way to add support for a WSVGA display, is it then 
possible to use the 1024x768 resolution but tell the xserver it only has a 
virtual screen of 1024x600? That would be dirty, but may eventually work as 
that complies to the situation described when switching from 1024x600 to 
1024x768 using the "gnome display preferences".

Do you have any hints how I could solve my problem?

Regards,
Dawid Nogens