Comment 9 for bug 373690

I have had a similar problem, though I'm not sure it has to do with xorg.
I get kernel error messages in /var/log/messages every time this happens, something like this (not always the same stack trace):

Jun 30 05:47:41 tangerine kernel: [ 608.220360] Pid: 7017, comm: pm-suspend Tainted: P 2.6.28-11-generic #42-Ubuntu
Jun 30 05:47:41 tangerine kernel: [ 608.220361] Call Trace:
Jun 30 05:47:41 tangerine kernel: [ 608.220364] [<c0139ab0>] warn_slowpath+0x60/0x80
Jun 30 05:47:41 tangerine kernel: [ 608.220367] [<c01537fa>] ? down_trylock+0x2a/0x40
Jun 30 05:47:41 tangerine kernel: [ 608.220369] [<c013a10d>] ? try_acquire_console_sem+0xd/0x30
Jun 30 05:47:41 tangerine kernel: [ 608.220373] [<c02c7290>] ? kobject_put+0x20/0x50
Jun 30 05:47:41 tangerine kernel: [ 608.220376] [<c0500ac6>] ? printk+0x18/0x1a
Jun 30 05:47:41 tangerine kernel: [ 608.220378] [<c0164fd0>] suspend_test_finish+0x80/0x90
Jun 30 05:47:41 tangerine kernel: [ 608.220380] [<c01650a6>] suspend_devices_and_enter+0xc6/0x160
Jun 30 05:47:41 tangerine kernel: [ 608.220382] [<c0500ac6>] ? printk+0x18/0x1a
Jun 30 05:47:41 tangerine kernel: [ 608.220384] [<c0165329>] enter_state+0xc9/0x100
Jun 30 05:47:41 tangerine kernel: [ 608.220386] [<c01653dd>] state_store+0x7d/0xc0
Jun 30 05:47:41 tangerine kernel: [ 608.220388] [<c0165360>] ? state_store+0x0/0xc0
Jun 30 05:47:41 tangerine kernel: [ 608.220390] [<c02c7154>] kobj_attr_store+0x24/0x30
Jun 30 05:47:41 tangerine kernel: [ 608.220393] [<c020ab02>] sysfs_write_file+0x92/0xf0
Jun 30 05:47:41 tangerine kernel: [ 608.220396] [<c01bdab8>] vfs_write+0x98/0x110
Jun 30 05:47:41 tangerine kernel: [ 608.220398] [<c020aa70>] ? sysfs_write_file+0x0/0xf0
Jun 30 05:47:41 tangerine kernel: [ 608.220399] [<c01bdbed>] sys_write+0x3d/0x70
Jun 30 05:47:41 tangerine kernel: [ 608.220402] [<c0103f6b>] sysenter_do_call+0x12/0x2f
Jun 30 05:47:41 tangerine kernel: [ 608.220403] ---[ end trace a50b6a42b0033182 ]---
Jun 30 05:47:41 tangerine kernel: [ 608.220721] Restarting tasks ... done.
Jun 30 05:47:41 tangerine kernel: [ 608.488524] usb 3-1: USB disconnect, address 4
Jun 30 05:47:41 tangerine kernel: [ 608.728165] usb 3-1: new full speed USB device using uhci_hcd and address 5