I've posted this issue in the Arch Linux forums and seem to have everyone there stumped.

It appears that something about fglrx is causing my system to hang when shutting down. Its all the way to "Power off" and then freezes. I ran some tests.

If I modprobe fglrx and try to shutdown without ever running an X server, it shuts down okay.

If I modprobe fglrx, run an X server, kill the X server and rmmod fglrx, the hang still occurs when I try to power down.

If I only run an X server on the vesa driver, everything works fine on shutdown.

Restarts of the computer always work fine -- it is only shutdowns that cause the hang.

I've looked through the logs and nothing seems to be different in them between a restart and shutdown. I believe the the hang may be occurring after logging has already stopped.

Running on Mobility Radeon 5830 (HP Envy 15 laptop Core i5) with Catalyst 10.7 -- Arch Linux x64, kernel 2.6.34. Any ideas?