[LAU] pops & clicks

[Pieter Palmers]

verymeta at riseup.net wrote:
> Thanks for the quick reply! I'll try to answer these questions...
> 
>> I assume you are using freebob and not ffado.
> 
> Yes.
> 
>> Some things to check:
>> * are you running jackd with the realtime flag?
> 
> Yes, 'realtime' is ticked in the qjackctl settings.
> 
>> * do you alleviate the priority of the ohci1394 interrupt above other
> interrupt sources? (e.g. with the rtirq)
> 
> No. I tried messing with IRQ priorities a couple of days back, but I
> didn't really know what I was doing and the only thing that happened was
> the menu bars on my desktop would disappear randomly when I started jack,
> I've reinstalled Ubuntu since then. Do you think it would help if I
> installed rtirq?

It might be good to raise your ohci1394 interrupt to a level higher than 
all non-critical things. This includes e.g. video card and USB stuff. 
Raising the period size should help too if irq priority is the issue.

> 
>> * does dmesg show anything special regarding 1394?
> 
> $ dmesg|grep 1394
> [   12.564436] ohci1394: fw-host0: OHCI-1394 1.1 (PCI): IRQ=[19] 
> MMIO=[fe4ff000-fe4ff7ff]  Max Packet=[2048]  IR/IT contexts=[8/8]
> [   13.822759] ieee1394: Host added: ID:BUS[0-00:1023] 
> GUID[384fc00039a11470]
> [   13.829370] ieee1394: Node added: ID:BUS[0-01:1023] 
> GUID[000d6c0b00e0fb02]
> [   20.828189] ieee1394: raw1394: /dev/raw1394 device initialized
> [   20.835615] NOTE: The dv1394 driver is unsupported and may be removed
> in a future Linux release. Use raw1394 instead.
> $
nothing special here

> 
>> * what firewire chipset do you use? (lspci | grep 1394)
> 
> $ lspci|grep 1394
> 03:01.4 FireWire (IEEE 1394): O2 Micro, Inc. Firewire (IEEE 1394) (rev 02)
> $
should work fine.

> 
>> * are you using -n3 (to specify the usage of 3 buffers of one period)?
> 
> Normally I just start jackd with qjackctl. Just now I tried starting it in
> the terminal with:
> 
> $ jackd -R -d freebob -n3
> 
> and it didn't make any difference to the sound.

ok, normally the defaults of qjackctl are sane.


Does the same problem also occur with other software? e.g. audio 
playback using aqualung or hydrogen output?

Greets,

Pieter