Re: [linux-audio-user] Problems with RP patch + hdsp + jackd at 96000

Thomas Charbonnel <thomas@email-addr-hidden> writes:

> Mario Lang wrote :
>> Hi.
>>
>> I recently patched my kernel with the RP patch by Ingo to get rid
>> of the many xruns I was getting with my brand new Multiface (PCI).
>>
>> THe result is somewhat strange, so I thought I'd post a summary here and see
>> if someone else has had similar problems:
>>
>> 1. jackd -d alsa -dhw:1 -p64
>> At 48kHz, jackd ran the whole night with SuperCollider connected
>> to some of its ports without a single xrun! This is a massive improvement.
>> 2. jackd -d alsa -dhw:1 -p64 -r96000
>> This used to work without the RP patch applied, it generated some
>> xruns, but it used to work. Now, using the RP patch, jackd seem
>> to simply hang. If I boot up the SuperCollider synthesis server,
>> it results in a "failed to start" message by SC. Normal jack clients
>> like jack_lsp do still work, but jackd exits after about 10 seconds or
>> so, claiming its watchdog killed it. Without -R, it runs without
>> dying, but no audio clients work.
>>
>> One indication that the problem is really originating from within
>> jackd is the fact that -v does not produce any of the load-statistic
>> output if used as argument to jackd.
>>
>> Linux lexx 2.6.12-rt-v0.7.50-10 #1 Wed Jun 22 14:59:13 CEST 2005 i686 GNU/Linux
>>
>> jackd version 0.99.0 tmpdir /dev/shm protocol 13
>
> Hi Mario,
>
> I just did some tests with 2.6.12-RT-V0.7.49-01 and can somehow
> reproduce this. In my case jack starts at 96kHz/p64 but stops really
> fast being xrun-flooded, but I run a more recent version (jackd version
> 0.100.1 tmpdir /dev/shm protocol 15).

I just found out it works at -r96000 -p128, totally reliably
without any xruns. Since that is effectively the same latency
as -r48000 -p64 (I think so, right?), I think I can
live with that.

> The culprit seems to be the 'Precise Pointer' at these settings.
> I set it to be the default a couple of months ago.
> I can run reliably @96kHz/p64 turning it off:
> amixer -c X cset numid=22 0 (where X is your alsa card number)

What are the downsides of turning "Precise Pointer" off?

> BTW how do you setup irq priorities ?

chrt -p 98 `pidof "IRQ 201"`

-- 
Thanks,
  Mario