Hi,
  I've just had something that may be similar on Gutsy (Toshiba A100-306 Equium)
00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller (rev 03)
00:02.1 Display controller: Intel Corporation Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller (rev 03)

I tried to watch the penguins at:
http://200.58.119.161/pinguinos/en/pinguinos_en_vivo.html

using the totem plugin in mozilla and got a black box rather than the video, I hit the 'open in Movie Player' on the menu and X hung and eventually restarted X in a not too happy state (gnome settings daemon didn't start?); I had compiz on and the machine had previously done a hibernate (not a suspend to RAM);  here is the bottom of the xorg.0.log I'm assuming all these errors came at the point it crashed?

Error in I830WaitLpRing(), timeout for 2 seconds
pgetbl_ctl: 0x3ffc0001 pgetbl_err: 0x0
ipeir: 0 iphdr: 1810000
LP ring tail: 16550 head: 16544 len: 1f801 start 0
eir: 0 esr: 0 emr: ffff
instdone: ffc0 instpm: 0
memmode: 306 instps: f0000
hwstam: fffe ier: a2 imr: 0 iir: 200
Ring at virtual 0xe5b0c000 head 0x16544 tail 0x16550 count 3
        000164c4: 00000000
        000164c8: 02000011
        000164cc: 00000000
        000164d0: 02000011
        000164d4: 00000000
        000164d8: 02000011
        000164dc: 00000000
        000164e0: 02000011
        000164e4: 00000000
        000164e8: 02000011
        000164ec: 00000000
        000164f0: 02000011
        000164f4: 00000000
        000164f8: 02000011
        000164fc: 00000000
        00016500: 02000011
        00016504: 00000000
        00016508: 02000011
        0001650c: 00000000
        00016510: 02000011
        00016514: 00000000
        00016518: 02000011
        0001651c: 00000000
        00016520: 02000011
        00016524: 00000000
        00016528: 02000011
        0001652c: 00000000
        00016530: 02000011
        00016534: 00000000
        00016538: 02000011
        0001653c: 00000000
        00016540: 01810000
        00016544: 00000000
Ring end
space: 131052 wanted 131064
(II) intel(0): [drm] removed 1 reserved context for kernel
(II) intel(0): [drm] unmapping 8192 bytes of SAREA 0x2efff000 at 0x2ba9e5461000

Fatal server error:
lockup


(II) AIGLX: Suspending AIGLX clients for VT switch
Error in I830WaitLpRing(), timeout for 2 seconds
pgetbl_ctl: 0x3ffc0001 pgetbl_err: 0x0
ipeir: 0 iphdr: 1810000
LP ring tail: 16578 head: 16544 len: 1f801 start 0
eir: 0 esr: 0 emr: ffff
instdone: ffc0 instpm: 0
memmode: 306 instps: f0000
hwstam: fffe ier: a2 imr: 0 iir: 200
Ring at virtual 0xe5b0c000 head 0x16544 tail 0x16578 count 13
        000164c4: 00000000
        000164c8: 02000011
        000164cc: 00000000
        000164d0: 02000011
        000164d4: 00000000
        000164d8: 02000011
        000164dc: 00000000
        000164e0: 02000011
        000164e4: 00000000
        000164e8: 02000011
        000164ec: 00000000
        000164f0: 02000011
        000164f4: 00000000
        000164f8: 02000011
        000164fc: 00000000
        00016500: 02000011
        00016504: 00000000
        00016508: 02000011
        0001650c: 00000000
        00016510: 02000011
        00016514: 00000000
        00016518: 02000011
        0001651c: 00000000
        00016520: 02000011
        00016524: 00000000
        00016528: 02000011
        0001652c: 00000000
        00016530: 02000011
        00016534: 00000000
        00016538: 02000011
        0001653c: 00000000
        00016540: 01810000
        00016544: 00000000
Ring end
space: 131012 wanted 131064

FatalError re-entered, aborting
lockup

I'm going to leave Compiz off - I've never had a crash like this without it on.