I am, and have had intermittent GPU lockups follow me across two separate installs. I first noticed the problem running GroovyMAME on Arch Linux. I assumed that the issue was caused by the hacked-together nature of that setup, so I decided to install GroovyLinux, where I am currently getting the very same error.
This leads me to believe that I have a hardware problem. I plan on ordering a different video card for testing, but I would also be curious to see if anyone else has experienced these problems.
In case it's of any use, this is what the kernel has to say about it:
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900071] radeon 0000:01:00.0: GPU lockup CP stall for more than 10000msec
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900074] ------------[ cut here ]------------
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900080] WARNING: at drivers/gpu/drm/radeon/radeon_fence.c:267 radeon_fence_wait+0x2bd/0x340()
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900082] Hardware name: A770E3
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900083] GPU lockup (waiting for 0x00000057 last fence id 0x00000056)
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900085] Modules linked in: oss_usb oss_hdaudio osscore r8169 psmouse mii tpm_tis pcspkr ppdev tpm fl$
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900162] Pid: 17237, comm: X Not tainted 3.0.2+ #1
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900164] Call Trace:
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900168] [<ffffffff81040d1d>] warn_slowpath_common+0x85/0x9d
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900171] [<ffffffff81040dd8>] warn_slowpath_fmt+0x46/0x48
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900174] [<ffffffff813318f3>] radeon_fence_wait+0x2bd/0x340
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900176] [<ffffffff8105ccf1>] ? wake_up_bit+0x2a/0x2a
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900179] [<ffffffff813470d1>] radeon_ib_get+0x109/0x1af
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900181] [<ffffffff81348363>] radeon_cs_ioctl+0x99/0x19e
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900184] [<ffffffff812f09d3>] drm_ioctl+0x285/0x362
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900186] [<ffffffff813482ca>] ? radeon_cs_parser_init+0x29e/0x29e
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900189] [<ffffffff81115d7d>] do_vfs_ioctl+0x451/0x4a0
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900192] [<ffffffff81201f2e>] ? security_file_permission+0x2e/0x33
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900194] [<ffffffff81115e22>] sys_ioctl+0x56/0x7c
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900196] [<ffffffff8110853b>] ? sys_read+0x4a/0x71
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900199] [<ffffffff81506102>] system_call_fastpath+0x16/0x1b
Oct 17 19:11:59 GroovyArcade kernel: [ 101.900201] ---[ end trace 2db85a87d092bf74 ]---