[asterisk-users] zaptel huge irq problem

[François Delawarde]

Hello,

I had noticed strange crackling sound on my phone calls going through my 
zaptel device (TDM400P), so i decided to check on possible timer issue, 
and found lots of issues on forums concerning the sensibility of zaptel 
with IRQs, and tried about everything: moving PCI slots, noapic and 
acpi=off boot options, play with different kernel options: 
iosched/preemption/timer/..., play with BIOS PCI options, change 
priorities, PCI latencies, IRQ balance, smp_afinity, ................ 
but impossible to come up with anything correcting that problem.

Any idea about this? Is it possible to force the timer to ztdummy (RTC 
timer) when you have a zap card plugged in? It's the only thing i could 
try to make it work.

Thanks,
François.

Just in case:

- Linux 2.6.18 with debian patches and xen enabled, asterisk running on 
dom0.

- Here is my zttest results under a bit of load:
# ./zttest
Opened pseudo zap interface, measuring accuracy...
99.609375% 99.609375% 99.218750% 99.316406% 99.804688% 99.414062% 99.121094%
99.511719% 99.121094% 99.316406% 99.707031% 99.707031% 98.730469% 
99.414062% 99.902344%
99.218750% 100.000000% 99.414062% 98.828125% 99.218750% 99.316406% 
98.449707% 100.000000%


- The card DOES NOT seem to share interrupts (checked also with lspci):
# cat /proc/interrupts
           CPU0              CPU1
  1:       1626          0        Phys-irq  i8042
  6:          3          0        Phys-irq  floppy
  8:          0          0        Phys-irq  rtc
  9:          0          0        Phys-irq  acpi
 14:         63          0        Phys-irq  ide0
 16:          1          0        Phys-irq  libata, eth3
 17:    6762583          0        Phys-irq  libata
 18:      13789          0        Phys-irq  libata
 19:   33459690          0        Phys-irq  eth1
 20:   19864325          0        Phys-irq  sky2, eth0
 21:  269250881          0        Phys-irq  wctdm
256:   77735119          0     Dynamic-irq  timer0
257:    3986325          0     Dynamic-irq  resched0
258:         37          0     Dynamic-irq  callfunc0
259:          0    4652748     Dynamic-irq  resched1
260:          0        139     Dynamic-irq  callfunc1
261:          0   28924306     Dynamic-irq  timer1
262:       1021          0     Dynamic-irq  xenbus
263:          0          0     Dynamic-irq  console
NMI:          0          0
LOC:          0          0
ERR:          0
MIS:          0