Distribution: debian unstable
Hardware Environment: AMD Athlon Thunderbird, nforce2-Chipset
Software Environment:
Problem Description:
The irq21 of this nforce2-board is triggered pretty often...

21: 1106804524   IO-APIC-level  ehci_hcd
10 seconds later:
21: 1108150969   IO-APIC-level  ehci_hcd

I didn't even use any USB-device in that period. Since my systems is running
pretty stable this issue (?) is not very important to me. But I have been
getting curious, if this behaviour is simply normal or a bug or whatever... It
happened with earlier kernel versions too...

Steps to reproduce:

I just booted...

system infos:

cat /proc/interrupts:
           CPU0       
  0:   57170836    IO-APIC-edge  timer
  1:      54302    IO-APIC-edge  i8042
  7:          0    IO-APIC-edge  parport0
  8:          4    IO-APIC-edge  rtc
  9:          0   IO-APIC-level  acpi
 12:     534130    IO-APIC-edge  i8042
 14:     237068    IO-APIC-edge  ide0
 15:        214    IO-APIC-edge  ide1
 16:      51349   IO-APIC-level  ide2, saa7134[0]
 17:     191473   IO-APIC-level  CMI8738
 19:    5059181   IO-APIC-level  nvidia
 20:    8242106   IO-APIC-level  ohci_hcd, eth0
 21: 1108150969   IO-APIC-level  ehci_hcd
 22:         88   IO-APIC-level  ohci_hcd
NMI:      20236 
LOC:   56976096 
ERR:          0
MIS:          0