I have exactly the same problem, and a very similar machine (Dell 500m)
I had Mandrake9.2 previously installed and had 1280x1024 resolution absolutely fine. I had 855patch installed but not 855resolution. Now when the X-server starts I get a scrambled mess of double overlapped imagery.
Now this is the really strange bit. If I access tty0 console (by pressing CTRL-ALT-F1) and then go back to the X server session (ALT+F7) then the login displays absolutely fine. But if I restart the X server (Alt+E on the login window) or logout of a user session (which implicitly restarts the x server) then the scrambled mess appears once more. Switch to console, back to X will resolve it though.
I have tried 855patch and 855resolution, but without success
Does anyone know why switching to console and back again sorts out the problem, I would like to automate that! Each time the X server re-starts a couple of lines are written to dmesg. I will post tonight to see if that helps anyone to help us.
Help on setting up video is at http://www.incunabulum.de/projects/c...laptop/xfree86
and here http://www.chzsoft.com.ar/855patch.html
and here http://projects.nudieman.com/500m/
I believe that the main problem is that Mandrake10.1 uses X.org, whilst Mandrake9.2 uses XFree86. Some major underlying changes may have been made since X.org forked and released the code used by Mandrake. Maybe the fixes are now incompatible? Can anyone help?