I've been running Kubuntu on this Dell XPS M1330 laptop with NVIDIA 8400M for four years with no problems. Suddenly when I upgraded from Oneiric (11.10) to Precise (12.04) I am getting crashes where X freezes at 100% CPU. The screen is frozen--sometimes the cursor still moves, sometimes it disappears. I can SSH in and see X at 100% CPU. I cannot switch to another VT. Sometimes I can SAK+K to kill X and restart KDM, and sometimes I can't, and I have to power off.
It seems to happen when playing YouTube videos in Flash in Firefox. I haven't had it crash at any other time so far.
It may be minutes, hours, or days between crashes.
I've tried 295.40 and 295.49, and both exhibit this freeze/crash.
This is what I see in dmesg:
[35437.091037] NVRM: GPU at 0000:01:00.0 has fallen off the bus.
[35437.091072] NVRM: GPU at 0000:01:00.0 has fallen off the bus.
[35438.672076] irq 16: nobody cared (try booting with the "irqpoll" option)
[35438.672082] Pid: 0, comm: BFS/0 Tainted: P C O 3.3.6-pf-adp+ #6
[35438.672085] Call Trace:
[35438.672093] [<c154ddf6>] ? printk+0x2d/0x2f
[35438.672099] [<c10b4139>] __report_bad_irq+0x29/0xd0
[35438.672103] [<c10b43ae>] note_interrupt+0x11e/0x1d0
[35438.672209] [<f9bce853>] ? nv_kern_isr+0x33/0x70 [nvidia]
[35438.672213] [<c10b21ee>] handle_irq_event_percpu+0x9e/0x200
[35438.672217] [<c10269e8>] ? default_spin_lock_flags+0x8/0x10
[35438.672221] [<c15560ad>] ? _raw_spin_lock_irqsave+0x2d/0x40
[35438.672225] [<c10b238b>] handle_irq_event+0x3b/0x60
[35438.672228] [<c10b4c20>] ? unmask_irq+0x30/0x30
[35438.672231] [<c10b4c6e>] handle_fasteoi_irq+0x4e/0xd0
[35438.672233] <IRQ> [<c155d3b2>] ? do_IRQ+0x42/0xc0
[35438.672240] [<c1084f2a>] ? tick_notify+0x2ca/0x3e0
[35438.672244] [<c155d2f0>] ? common_interrupt+0x30/0x38
[35438.672247] [<c1556035>] ? _raw_spin_unlock_irqrestore+0x15/0x20
[35438.672251] [<c108462d>] ? clockevents_notify+0x3d/0x100
[35438.672255] [<c13168d5>] ? lapic_timer_state_broadcast+0x36/0x39
[35438.672259] [<c13169eb>] ? acpi_idle_enter_simple+0x113/0x133
[35438.672263] [<c1448d9d>] ? cpuidle_idle_call+0xad/0x250
[35438.672267] [<c100174c>] ? cpu_idle+0x9c/0xe0
[35438.672271] [<c1531825>] ? rest_init+0x5d/0x68
[35438.672275] [<c17f5745>] ? start_kernel+0x357/0x35d
[35438.672278] [<c17f517f>] ? loglevel+0x2b/0x2b
[35438.672281] [<c17f5078>] ? i386_start_kernel+0x78/0x7d
[35438.672366] [<f9bce820>] nv_kern_isr
[35438.672369] Disabling IRQ #16
I've never had a problem like this until "upgrading" to these newer drivers that come with 12.04 Precise. My laptop is now totally unreliable.