LinuxQuestions.org - Radeon driver - disable 3d acceleration?

I'm trying to set up the Mobility Radeon 9000 card in my laptop to use a dual-head setup. I want to run the LCD on my laptop at 1600x1200 and the external LCD at 1024x768.

I am using the "MergedFB" option in the xorg Radeon driver to accomplish this. If I set the MetaMode option to "1024x768-1024x768" (ie virtual resolution of 2048x768) then it works fine - at 1024x768 on both screens. However, if I set this option to "1600x1200-1024x768" (combined resolution of 2624x1200) then the X server fails to start.

Reading the "man radeon" page, I noticed this line:

Quote:

The maximum framebuffer size that the 2D acceleration engine can handle is 8192x8192. The maximum framebuffer size that the 3D engine can handle is 2048x2048.

So, I set the NoAccel option to "true" - this turns off ALL hardware acceleration - then the desired screen resolutions ("1600x1200-1024x768") work perfectly. BUT because there is no 2D acceleration, the system is very unresponsive, dragging windows is very jerky, etc.

So, my question is this: with the Xorg "radeon" driver, is it possible to turn off 3D acceleration but leave 2D acceleration enabled? I can't seem to find an option to do this anywhere.

Alternatively: is there a better way to accomplish this dual monitor setup?

Thanks in advance!