Running "vbetool vbestate save" is sufficient to prevent X from properly starting up, leaving a blank screen. Killing X "works" but leaves a static cursor at the top left.

inteldrmfb is in use on 945-based hw.

Leaving X "running", backtraces such as the following start appearing. I've also observed unrelated tasks getting stuck (the scheduler can get caught up in this too). Something not being unlocked...?

INFO: task events/0:5 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
events/0      D f722b4e0     0     5      2
 f706bf60 00000046 f7040e00 f722b4e0 f62cc0ac f7040f90 f64f3228 c011849e
 f62cc080 c04dfd3c f7350d58 f7040e00 f70d6000 f706bf7c c03a6fbf f7350d5c
 f7350d5c f7040e00 f7350d58 f70d6bbc f706bf8c c03a6f31 000001f4 f7350d48
Call Trace:
 [<c011849e>] ? set_next_entity+0x14/0x39
 [<c03a6fbf>] __mutex_lock_slowpath+0x42/0x64
 [<c03a6f31>] mutex_lock+0x19/0x1d
 [<c026b10a>] i915_gem_retire_work_handler+0x22/0x57
 [<c026b0e8>] ? i915_gem_retire_work_handler+0x0/0x57
 [<c01284dc>] worker_thread+0xe4/0x153
 [<c012a82a>] ? autoremove_wake_function+0x0/0x30
 [<c01283f8>] ? worker_thread+0x0/0x153
 [<c012a6bd>] kthread+0x42/0x69
 [<c012a67b>] ? kthread+0x0/0x69
 [<c0102fd3>] kernel_thread_helper+0x7/0x10