Comment 74 for bug 177895

Barteq, ..just to add, here are the deltas of IRQ's on your system from the last set of /proc/interrupts capture from your data.. showing a worryingly high IRQ 0 hit.

              CPU0 CPU1
  0: 23573 23612 IO-APIC-edge timer
  1: 558 562 IO-APIC-edge i8042
  8: 0 0 IO-APIC-edge rtc
  9: 94 95 IO-APIC-fasteoi acpi
 12: 0 0 IO-APIC-edge i8042
 14: 0 0 IO-APIC-edge libata
 15: 0 0 IO-APIC-edge libata
 16: 0 0 IO-APIC-fasteoi uhci_hcd:usb3
 17: 0 0 IO-APIC-fasteoi uhci_hcd:usb1
 18: 0 0 IO-APIC-fasteoi uhci_hcd:usb2
 19: 0 0 IO-APIC-fasteoi ehci_hcd:usb6
 22: 0 0 IO-APIC-fasteoi uhci_hcd:usb5
 23: 0 2 IO-APIC-fasteoi ehci_hcd:usb7
217: 2090 2047 PCI-MSI-edge ahci
NMI: 0 0 Non-maskable interrupts
LOC: 13271 12598 Local timer interrupts
RES: 12201 11276 Rescheduling interrupts
CAL: 14 6 function call interrupts
TLB: 65 61 TLB shootdowns
TRM: 0 0 Thermal event interrupts
SPU: 0 0 Spurious interrupts
ERR: 0
MIS: 0

and lspci shows that the following devices share IRQ 0:

00:01.0 PCI bridge [0604]: Intel Corporation Mobile PM965/GM965/GL960 PCI Express Root Port [8086:2a01] (rev 0c) (prog-if 00 [Normal decode])
00:1b.0 Audio device [0403]: Intel Corporation 82801H (ICH8 Family) HD Audio Controller [8086:284b] (rev 03)
00:1c.0 PCI bridge [0604]: Intel Corporation 82801H (ICH8 Family) PCI Express Port 1 [8086:283f] (rev 03) (prog-if 00 [Normal decode])
00:1c.1 PCI bridge [0604]: Intel Corporation 82801H (ICH8 Family) PCI Express Port 2 [8086:2841] (rev 03) (prog-if 00 [Normal decode])
00:1c.2 PCI bridge [0604]: Intel Corporation 82801H (ICH8 Family) PCI Express Port 3 [8086:2843] (rev 03) (prog-if 00 [Normal decode])
00:1c.3 PCI bridge [0604]: Intel Corporation 82801H (ICH8 Family) PCI Express Port 4 [8086:2845] (rev 03) (prog-if 00 [Normal decode])
00:1c.4 PCI bridge [0604]: Intel Corporation 82801H (ICH8 Family) PCI Express Port 5 [8086:2847] (rev 03) (prog-if 00 [Normal decode])
01:00.0 VGA compatible controller [0300]: nVidia Corporation Quadro NVS 140M [10de:0429] (rev a1) (prog-if 00 [VGA controller])
03:00.0 Network controller [0280]: Intel Corporation PRO/Wireless 4965 AG or AGN Network Connection [8086:4230] (rev 61)

..one of this may be the culprit. But first I'd like to see of acpi=noirq helps first.

Thanks, Colin.