> Take a look at /proc/interrupts to see if you have something firing > that you do not expect. I took a look and this is what I see: # cat /proc/interrupts CPU0 2: 0 PNX Level IRQ GIC 7: 0 PNX Level IRQ Timer 10: 661 PNX Level IRQ pnx8550-1 11: 605 PNX Level IRQ pnx8550-2 13: 1 PNX Level IRQ ohci_hcd:usb2 23: 583 PNX Level IRQ i2c 24: 845 PNX Level IRQ i2c 28: 334 PNX Level IRQ pnx8xxx-uart 34: 1 PNX Level IRQ Drawing Engine 47: 0 PNX Level IRQ vmsp1 49: 0 PNX Level IRQ vmsp2 55: 15876 PNX Level IRQ libata, ehci_hcd:usb1, ohci_hcd:usb3, ohci_hcd:usb4, eth0 75: 18 PNX Level IRQ i2c 78: 192 PNX Level IRQ i2c 79: 80239 PNX Level IRQ timer 80: 19 PNX Level IRQ Monotonic timer ERR: 99373 It looks like there are quite a few devices on irq 55 even before I load my module. Is it at all possible that I could get my device to use a different interrupt line? or is this totally restricted by hardware? Also what does the "ERR" mean? Does this keep a tally of errors? If so does 99K errors seem high? > If you are sharing the same IRQ as USB, do you request the IRQ as > shared? Does the USB as well? My device does, yes. At this point I have to assume the USB driver is too. But even if that was the problem, it wouldn't explain why the error also happens when I don't request the interrupt at all. Thanks, Jon