[asterisk-users] wctdm24xx IRQ missing

[Shaun Ruffell]

On Thu, Aug 04, 2011 at 09:28:43AM +0200, voip crazy wrote:
> Hello all,
> 
> I just instaled a tdm2400 Digium card on my asterisk box. When it
> boots, I can see some error messages in "dmesg".
> 
> wctdm24xxp 0000:21:08.0: Missed interrupt. Increasing latency to 8 ms
> in order to compensate.
> wctdm24xxp 0000:21:08.0: Missed interrupt. Increasing latency to 10 ms
> in order to compensate.
> wctdm24xxp 0000:21:08.0: Missed interrupt. Increasing latency to 11 ms
> in order to compensate.
> wctdm24xxp 0000:21:08.0: Missed interrupt. Increasing latency to 12 ms
> in order to compensate.
> wctdm24xxp 0000:21:08.0: Missed interrupt. Increasing latency to 13 ms
> in order to compensate.
> 
> I try to change the IRQ of the card, using the "setpci" command,
> without success.
> I am using dadhi 2.2.1 and asterisk 1.4.24
> 
> Has anyone the same problem?
> How could I change to fix this errors?
> 
> Any clue will be wellcomed.

That is indidicating that something on your host is preventing the wctdm24xxp
from being able to service it's interrupt within the time frame.  13 ms of
interrupt latency is very high.  The two cases that I normally see that are:

a) Hard drive is operating in some PIO mode and making the interrupt handler
take a very long time.  You can normally see this if 'hdparam -t /dev/hda'
(and it's normally hda not sda) takes less than 10 MB/s. I have seen this as a
default mode on some early SSD drives.

b) Your running a debug kernel on a slow / low power system.

I would also recommend updating to 2.5.0-rc2 (which will soon be released as
2.5.0) since there are some improvements in the efficiency of the wctdm24xxp
interrupt handler.

-- 
Shaun Ruffell
Digium, Inc. | Linux Kernel Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
Check us out at: www.digium.com & www.asterisk.org