Trouble with resolution on Radeon X1250

Hey everyone,

I am currently trying to build a linux image for our currently Windows-running thin clients at work. We use Fujitsu Futro S550 and S550-2 which are, on the paper, very similar. Both have the M960E chipset, both are using a Radeon X1250 graphics chip. The only obvious difference is the processor, changing from a Sempron 2100+ to a Sempron 200U, both 1 GHz.

Now comes the “funny” part: Where the S550-2 is perfectly using the native resolution of the connected display (1920x1080 or 1280x1024) the S550 always boots with 640x480 - although they use the same chip. The S550 won’t even detect possible resolutions when I go to System -> Hardware -> Screens. I always have to do “xrandr --output DVI-0 --auto” after a reboot, then it works.

I really need to get this fixed because I wanted to use the same image on both clients. Any ideas why this could happen? I also did “lspci -nn -k” and the IDs and drivers are the same.

Ressources:
S550 Data
S550-2 Data