After upgrading to Ubuntu Maverick (kernel upgrade from 2.6.23.27 to 2.6.33.25), I'm finding that the GPU is locking up during computer startup. I also find that from time to time that when I type in my password in GDM it doesn't load my normal desktop environment and seems to "hang". 

I don't believe it's a crash, as the GPU gets reset, though this can take a while. 

The following is from kern.log:

Dec 21 16:45:51 ubuntu kernel: [ 54.757121] WARNING: at /build/buildd/linux-2.6.35/drivers/gpu/drm/radeon/radeon_fence.c:235 radeon_fence_wait+0x23e/0x290 [radeon]()
Dec 21 16:45:51 ubuntu kernel: [ 54.757128] Hardware name: MM061
Dec 21 16:45:51 ubuntu kernel: [ 54.757134] GPU lockup (waiting for 0x0000000E last fence id 0x0000000D)
Dec 21 16:45:51 ubuntu kernel: [ 54.757139] Modules linked in: xt_limit xt_tcpudp ipt_LOG ipt_MASQUERADE xt_DSCP ipt_REJECT nf_conntrack_irc nf_conntrack_ftp xt_state binfmt_misc parport_pc ppdev joydev iptable_nat nf_nat nf_conntrack_ipv4 nf_conntrack nf_defrag_ipv4 iptable_mangle iptable_filter ip_tables x_tables snd_hda_codec_idt snd_hda_intel arc4 snd_hda_codec snd_hwdep snd_pcm snd_seq_midi radeon snd_rawmidi snd_seq_midi_event iwl3945 ttm snd_seq iwlcore drm_kms_helper snd_timer mac80211 snd_seq_device i8k sbp2 r852 sm_common dell_wmi nand nand_ids nand_ecc mtd snd dell_laptop psmouse ieee1394 dcdbas serio_raw drm intel_agp cfg80211 soundcore snd_page_alloc video output agpgart i2c_algo_bit lp parport b44 sdhci_pci sdhci firewire_ohci led_class firewire_core ssb mii crc_itu_t
Dec 21 16:45:51 ubuntu kernel: [ 54.757304] Pid: 1194, comm: Xorg Not tainted 2.6.35-23-generic #40-Ubuntu
Dec 21 16:45:51 ubuntu kernel: [ 54.757307] Call Trace:
Dec 21 16:45:51 ubuntu kernel: [ 54.757318] [<c014acf2>] warn_slowpath_common+0x72/0xa0
Dec 21 16:45:51 ubuntu kernel: [ 54.757338] [<f88862fe>] ? radeon_fence_wait+0x23e/0x290 [radeon]
Dec 21 16:45:51 ubuntu kernel: [ 54.757361] [<f88862fe>] ? radeon_fence_wait+0x23e/0x290 [radeon]
Dec 21 16:45:51 ubuntu kernel: [ 54.757366] [<c014adc3>] warn_slowpath_fmt+0x33/0x40
Dec 21 16:45:51 ubuntu kernel: [ 54.757388] [<f88862fe>] radeon_fence_wait+0x23e/0x290 [radeon]
Dec 21 16:45:51 ubuntu kernel: [ 54.757397] [<c0165eb0>] ? autoremove_wake_function+0x0/0x50
Dec 21 16:45:51 ubuntu kernel: [ 54.757417] [<f8886a21>] radeon_sync_obj_wait+0x11/0x20 [radeon]
Dec 21 16:45:51 ubuntu kernel: [ 54.757430] [<f86dde67>] ttm_bo_wait+0xe7/0x180 [ttm]
Dec 21 16:45:51 ubuntu kernel: [ 54.757454] [<f889c069>] radeon_gem_wait_idle_ioctl+0x89/0x110 [radeon]
Dec 21 16:45:51 ubuntu kernel: [ 54.757474] [<f84b898d>] drm_ioctl+0x1ad/0x430 [drm]
Dec 21 16:45:51 ubuntu kernel: [ 54.757501] [<f889bfe0>] ? radeon_gem_wait_idle_ioctl+0x0/0x110 [radeon]
Dec 21 16:45:51 ubuntu kernel: [ 54.757511] [<c010b072>] ? restore_i387_xstate+0xe2/0x210
Dec 21 16:45:51 ubuntu kernel: [ 54.757517] [<c02189d2>] ? rw_verify_area+0x62/0xd0
Dec 21 16:45:51 ubuntu kernel: [ 54.757521] [<c0226a22>] vfs_ioctl+0x32/0xb0
Dec 21 16:45:51 ubuntu kernel: [ 54.757535] [<f84b87e0>] ? drm_ioctl+0x0/0x430 [drm]
Dec 21 16:45:51 ubuntu kernel: [ 54.757538] [<c02272b9>] do_vfs_ioctl+0x79/0x2d0
Dec 21 16:45:51 ubuntu kernel: [ 54.757542] [<c01021d6>] ? restore_sigcontext+0xc6/0xe0
Dec 21 16:45:51 ubuntu kernel: [ 54.757546] [<c0227577>] sys_ioctl+0x67/0x80
Dec 21 16:45:51 ubuntu kernel: [ 54.757551] [<c05c99f4>] syscall_call+0x7/0xb

The following is from lspci:

chris@ubuntu:~$ lspci
00:00.0 Host bridge: Intel Corporation Mobile 945GM/PM/GMS, 943/940GML and 945GT Express Memory Controller Hub (rev 03)
00:01.0 PCI bridge: Intel Corporation Mobile 945GM/PM/GMS, 943/940GML and 945GT Express PCI Express Root Port (rev 03)
00:1b.0 Audio device: Intel Corporation N10/ICH 7 Family High Definition Audio Controller (rev 01)
00:1c.0 PCI bridge: Intel Corporation N10/ICH 7 Family PCI Express Port 1 (rev 01)
00:1c.3 PCI bridge: Intel Corporation N10/ICH 7 Family PCI Express Port 4 (rev 01)
00:1d.0 USB Controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #1 (rev 01)
00:1d.1 USB Controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #2 (rev 01)
00:1d.2 USB Controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #3 (rev 01)
00:1d.3 USB Controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #4 (rev 01)
00:1d.7 USB Controller: Intel Corporation N10/ICH 7 Family USB2 EHCI Controller (rev 01)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev e1)
00:1f.0 ISA bridge: Intel Corporation 82801GBM (ICH7-M) LPC Interface Bridge (rev 01)
00:1f.2 IDE interface: Intel Corporation 82801GBM/GHM (ICH7 Family) SATA IDE Controller (rev 01)
00:1f.3 SMBus: Intel Corporation N10/ICH 7 Family SMBus Controller (rev 01)
01:00.0 VGA compatible controller: ATI Technologies Inc Radeon Mobility X1400
03:00.0 Ethernet controller: Broadcom Corporation BCM4401-B0 100Base-TX (rev 02)
03:01.0 FireWire (IEEE 1394): Ricoh Co Ltd R5C832 IEEE 1394 Controller
03:01.1 SD Host controller: Ricoh Co Ltd R5C822 SD/SDIO/MMC/MS/MSPro Host Adapter (rev 19)
03:01.2 System peripheral: Ricoh Co Ltd R5C592 Memory Stick Bus Host Adapter (rev 0a)
03:01.3 System peripheral: Ricoh Co Ltd xD-Picture Card Controller (rev 05)
0b:00.0 Network controller: Intel Corporation PRO/Wireless 3945ABG [Golan] Network Connection (rev 02)

Interestingly, I'm also randomly having issues logging in via gdm as the screen seems to lockup. One time, the mouse stopped working altogether. This may be something else however, but thought it worthwhile noting it.

ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: xorg 1:7.5+6ubuntu3
ProcVersionSignature: Ubuntu 2.6.32-25.45-generic 2.6.32.21+drm33.7
Uname: Linux 2.6.32-25-generic i686
Architecture: i386
DRM.card0.LVDS.1:
 status: connected
 enabled: enabled
 dpms: On
 modes: 1280x800 1280x720 1152x768 1024x768 800x600 848x480 720x480 640x480
 edid-base64: AP///////wBMowAAAAAAAAAQAQOAIRV4Cof1lFdPjCcnUFQAAAABAQEBAQEBAQEBAQEBAQEBxxsAoFAgFzAwICYAS88QAAAZAAAADwAAAAAAAAAAACOHAmQAAAAA/gBERjA1NgMxNTRYMwogAAAA/gAnQFBagbDZ/wEBCiAgAJ0=