Some thing more or less, happens to me.  UI becomes unresponsive.  I can still move the mouse but all kep presses and clicks are uneffective.  I can ssh in from an another computer and reboot.  This happens about once an hour, doing nothing more than browsing the web, running a terminal and checking email.


Computer has GeForce 7300 LE] (rev a1),.
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 23
model name      : Intel(R) Core(TM)2 Duo CPU     E7200  @ 2.53GHz
stepping        : 6

messages in log:

Aug 19 12:42:59 daveb-Vostro-200 kernel: [  220.950182] NVRM: os_pci_init_handle: invalid context!
Aug 19 12:42:59 daveb-Vostro-200 kernel: [  220.950187] NVRM: os_pci_init_handle: invalid context!
Aug 19 12:42:59 daveb-Vostro-200 kernel: [  220.950196] NVRM: os_map_kernel_space: can't map 0xd0000000, invalid context!
Aug 19 12:42:59 daveb-Vostro-200 kernel: [  220.950199] NVRM: os_pci_init_handle: invalid context!
Aug 19 12:43:00 daveb-Vostro-200 kernel: [  222.151511] NVRM: GPU at 0000:01:00.0 has fallen off the bus.
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224598] irq 16: nobody cared (try booting with the "irqpoll" option)
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224605] Pid: 1183, comm: Xorg Tainted: P           O 3.2.0-29-generic-pae #46-Ubuntu
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224608] Call Trace:
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224617]  [<c158f812>] ? printk+0x2d/0x2f
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224624]  [<c10c09b9>] __report_bad_irq+0x29/0xd0
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224629]  [<c10c0c14>] note_interrupt+0x104/0x150
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224633]  [<c10beade>] handle_irq_event_percpu+0x9e/0x200
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224639]  [<c1036628>] ? default_spin_lock_flags+0x8/0x10
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224644]  [<c102d6e0>] ? unmask_ioapic+0x50/0x60
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224648]  [<c10bec7b>] handle_irq_event+0x3b/0x60
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224652]  [<c10c1420>] ? unmask_irq+0x30/0x30
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224657]  [<c10c146e>] handle_fasteoi_irq+0x4e/0xd0
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224660]  <IRQ>  [<c15acf12>] ? do_IRQ+0x42/0xc0
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224668]  [<c106114c>] ? irq_exit+0x3c/0xa0
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224672]  [<c15acf1b>] ? do_IRQ+0x4b/0xc0
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224676]  [<c15acd70>] ? common_interrupt+0x30/0x38
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224681]  [<c106007b>] ? ftrace_raw_event_softirq+0x4b/0xa0
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224686]  [<c15a00e0>] ? fill_powernow_table_pstate+0x78/0x127
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224691]  [<c1017266>] ? read_tsc+0x6/0x40
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224697]  [<c1083944>] ? getnstimeofday+0x54/0x120
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224702]  [<c1083a56>] ? do_gettimeofday+0x16/0x40
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224706]  [<c105f8a3>] ? sys_gettimeofday+0x23/0x70
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224710]  [<c15ac7df>] ? sysenter_do_call+0x12/0x28
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224713] handlers:
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224717] [<c140f2d0>] usb_hcd_irq
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224847] [<f9a26820>] nv_kern_isr
Aug 19 12:43:01 daveb-Vostro-200 kernel: [  223.224850] Disabling IRQ #16