[Avila] irq27: nobody cared

[David Acker]

Tim Harvey wrote:
> What are the details of the kernel your using?  Exactly how often are you seeing this error?  I haven't noticed this on my 2.6.15 kernel patched (the irq27 that is, I've had no dealings with USB mass storage) with IAL 1.4 other than occasionally when the driver unloads.
> 
> Tim
> 

We are using the kernel provided by gateworks but with newer versions of 
madwifi and hostap.  I can get the "nobody cared" spurious interrupt 
error on irq27 with enough radio traffic on minipci J1 and on irq28 
enough usb storage.  Also, I can put an intel e100 minipci adapter in 
minipci J1 instead of an atheros radio and get the same message for irq 
27.  The rate of occurrence depends on the traffic pattern.  irq27 will 
happen several times in an overnight test with data one wireless client 
sending TCP to the avila board which is then forwarding to an ethernet 
port.  Rates are around 20 Mbps.  With USB, irq28 will happens around 
every 10-15th time we copy a 20 MB file from USB to a tmpfs filesystem 
in a loop.

The "Badness in dma_free_coherent" appears to be a known bug that 
started in 2.6.15.  This occurs more often, like every 3rd time I copy a 
file, although sometimes I get multiple messages for one copy attempt. 
There have been several changes in the arm dma and mm areas since 
2.6.15.  This is why I would like to know which 2.6.15 kernel was used 
as a base for the gateworks CD.

Oh, and while we are on the topic of interrupts...why is the intel 
ethernet port hooked to irq18 which is supposed to be the performance 
monitor according to the gateworks docs?  It is generating LOTS of 
interrupts, like thousands per second..even if no ethernet cable is 
plugged in.

bash-3.1# cat /proc/interrupts
            CPU0
   0:          0   osal
   1:        192   osal
   2:        191   osal
   3:          0   ixp400_eth
   5:      26053   IXP4xx Timer Tick
  15:        263   serial
  18:     969402   ixp400_eth
  27:      40444   wifi0
  28:          0   ehci_hcd:usb1, ohci_hcd:usb2, ohci_hcd:usb3
Err:          0
bash-3.1# cat /proc/uptime
264.34 186.88
bash-3.1

That's around 3,672 interrupts a second without having ethernet plugged in!
-Ack