[asterisk-users] Multiple cards using same IRQ - getting IRQ errors and hissing

[Johan Wilfer]

On 2011-05-03 16:32, Dean Hoover wrote:
> I am running Asterisk 1.16.2.13, dahdi 2.4.0 and libpri 1.4.11.4 on an
> HP ML110 G6 using Ubuntu Linux 10.04 LTS.
>
> I have two Digium TE121 single T1 port cards and a Digium AEX800
> 8-port FXS card.  All PCI Express cards.
>
> Co-workers are hearing hissing sounds on some calls, and I am getting
> IRQ errors when running "dahdi show status".
>
> I see that sharing IRQs for Digium cards isn't recommended, so I'm
> trying to set it so each card gets its own.  From the few web sites
> I've read so far, including Digium's FAQ site, I've added ACPI and
> verified that the BIOS does not give me the ability to manually set
> the IRQ.  I've even taken one of the TE121's out of the server (it
> isn't being used anyways).  Everything I've done so far has not fixed
> it.  All the cards (as well as USB1) all use IRQ 16.
>
> The other option given was to use setpci, but I am unfamiliar with
> that command.  I did what I could to try and find the setting (based
> on what the man page on Ubuntu's web site) where I could see the value
> 16, but not getting anywhere.
>
> I know that this is more of an Asterisk forum than Digium.  If I need
> to put in a case at Digium I will, but wanted to see if there were any
> suggestions here before I pursued that.
>
> Any help would be appreciated.
>
> Dean Hoover
>

A month ago I had similar problems with a HP DL360g6 and a HP DL380g7 
running Debian 5 "Lenny".
In the HP DL360g6 I had one TE121. I noticed IRQ misses and the problem 
was easily reproduced
by running dahdi_maint to enable loopback and patlooptest while 
compiling asterisk to create some i/o.

When I installed Debian 6 "Squeeze" instead the problem went away. 
Tested with both servers above.
On this page I found some information about APIC (Advanced Programmable 
Interupt Controller)
http://www.asteriskguru.com/tutorials/pci_irq_apic_tdm_ticks_te410p_te405p_noise.html 
(quite old but informative)

I haven't got the time to verify the root cause of the problem yet (I've 
planned to do this at the end of this month)
but my theory is that it has something to do with the kernels APIC 
handling that was fixed between Debian 5 and 6.

Maybe you experience something similar?

/Johan

-- 
Johan Wilfer                 email: johan at jttech.se
JT Tech | Utvecklare         webb: http://jttech.se
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