Ok I just had crash after my system had been on for a couple of hours. (first one since adding pci=nomsi)
Below is the kernel trace:

I notice radeon and drm in the output, is this related to this bug or should I open a new one?

Mar 26 21:20:02 danny-laptop kernel: [15086.551703] BUG: unable to handle kernel paging request at 00001187
Mar 26 21:20:02 danny-laptop kernel: [15086.551716] IP: [<f822bc68>] drm_mm_search_free_in_range+0x28/0xe0 [drm]
Mar 26 21:20:02 danny-laptop kernel: [15086.551749] *pde = 760b5067 
Mar 26 21:20:02 danny-laptop kernel: [15086.551753] Oops: 0000 [#1] SMP 
Mar 26 21:20:02 danny-laptop kernel: [15086.551758] last sysfs file: /sys/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0C0A:00/power_supply/BAT1/charge_full
Mar 26 21:20:02 danny-laptop kernel: [15086.551763] Modules linked in: wlan_tkip binfmt_misc ppdev snd_hda_codec_realtek fbcon tileblit font bitblit snd_hda_intel softcursor snd_hda_codec snd_hwdep wlan_scan_sta snd_pcm_oss snd_mixer_oss snd_pcm ath_rate_sample snd_seq_dummy snd_seq_oss snd_seq_midi snd_rawmidi pcmcia joydev ath_pci snd_seq_midi_event radeon ttm drm_kms_helper snd_seq drm i2c_algo_bit yenta_socket snd_timer snd_seq_device snd rsrc_nonstatic soundcore shpchp pcmcia_core snd_page_alloc ati_agp i2c_piix4 agpgart video wlan ath_hal(P) psmouse output serio_raw lp parport usbhid 8139too hid 8139cp mii pata_atiixp sata_sil
Mar 26 21:20:02 danny-laptop kernel: [15086.551828] 
Mar 26 21:20:02 danny-laptop kernel: [15086.551833] Pid: 919, comm: Xorg Tainted: P           (2.6.32-17-generic #26-Ubuntu) Satellite L30
Mar 26 21:20:02 danny-laptop kernel: [15086.551837] EIP: 0060:[<f822bc68>] EFLAGS: 00213293 CPU: 1
Mar 26 21:20:02 danny-laptop kernel: [15086.551849] EIP is at drm_mm_search_free_in_range+0x28/0xe0 [drm]
Mar 26 21:20:02 danny-laptop kernel: [15086.551852] EAX: 00000001 EBX: 00000001 ECX: 00001187 EDX: 00000000
Mar 26 21:20:02 danny-laptop kernel: [15086.551855] ESI: 00001187 EDI: 00000001 EBP: e6a79ca8 ESP: e6a79c80
Mar 26 21:20:02 danny-laptop kernel: [15086.551859]  DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
Mar 26 21:20:02 danny-laptop kernel: [15086.551862] Process Xorg (pid: 919, ti=e6a78000 task=e4cf19a0 task.ti=e6a78000)
Mar 26 21:20:02 danny-laptop kernel: [15086.551865] Stack:
Mar 26 21:20:02 danny-laptop kernel: [15086.551867]  db490a80 00000000 00000000 e3b58500 e6b5c42c 00000001 00000000 e6a79d58
Mar 26 21:20:02 danny-laptop kernel: [15086.551876] <0> f6809d14 e6a79d28 e6a79cdc f8387579 00000000 00008000 00000001 00285906
Mar 26 21:20:02 danny-laptop kernel: [15086.551885] <0> e6b5c42c 00000000 00008000 f6a9324c 00000002 00000001 00000000 e6a79d38
Mar 26 21:20:02 danny-laptop kernel: [15086.551895] Call Trace:
Mar 26 21:20:02 danny-laptop kernel: [15086.551910]  [<f8387579>] ? ttm_bo_man_get_node+0x79/0xd0 [ttm]
Mar 26 21:20:02 danny-laptop kernel: [15086.551917]  [<f83877c4>] ? ttm_bo_mem_space+0x1f4/0x4d0 [ttm]
Mar 26 21:20:02 danny-laptop kernel: [15086.551925]  [<f83865cb>] ? ttm_bo_unmap_virtual+0x4b/0x60 [ttm]
Mar 26 21:20:02 danny-laptop kernel: [15086.551933]  [<f838832e>] ? ttm_bo_move_buffer+0xae/0x120 [ttm]
Mar 26 21:20:02 danny-laptop kernel: [15086.551941]  [<f8388436>] ? ttm_bo_validate+0x96/0x130 [ttm]
Mar 26 21:20:02 danny-laptop kernel: [15086.551948]  [<f838863b>] ? ttm_bo_init+0x16b/0x1d0 [ttm]
Mar 26 21:20:02 danny-laptop kernel: [15086.551977]  [<f848b56d>] ? radeon_bo_create+0xed/0x1f0 [radeon]