Re: [LAU] hdsp not happy with recent kernels

On Thu, September 13, 2012 5:00 pm, Paul Davis wrote:
> On Thu, Sep 13, 2012 at 6:51 PM, Len Ovens <len@email-addr-hidden> wrote:
>
>>
>> It depends how pulse is set up. If pulse is also connected to the
>> internal
>> card (that is the internal card is not turned off in pulse) Then the
>> pulse
>> jacksink/source modules will hold jack to whatever that internal card is
>> doing.
>
>
> there is some confusion here. the pulse jacksink/source modules connect
> pulse to JACK, not vice-versa. JACK will be using whatever hardware it was
> told to use. the only situation in which JACK routes audio via Pulse is if
> the user tells JACK to use an ALSA PCM device that is actually a pulse
> pseudo-device (eg. "default" on a system set up with Pulse as the
> default).

If pulse has the module-jack-source loaded, then jack feeds audio to
pulse. and if module-jack-sink is loaded then pulse feeds audio to jack.
Normally they are both loaded at the same time by module-jackdbus-detect.

It is possible to route audio in through one device to jack through pulse
and out to another device. Pulse has routing too... much harder to use
though.

I have a netbook with intel HDA audio. When I use Jack to run it the
lowest latency I can get jack to start at is -p128. At that latency the
wireless driver causes xruns on a regular basis. I also have an ART USB
audio interface. If I have manually unloaded the module-jackdbus-detect
module from pulse, The USB audio interface will start with jack with the
latency at -p 64 and no xruns. If I reload the same module I can now only
start the USB sound at -p 128 and I get the same xruns...on the USB card.
now if I configure pulse to ignore the internal sound interface...even
with the module-jackdbus-detect module loaded and streaming sound through
pulse and then jack... I can start jack at -p 64 with no problem. Pulse
does in some cases affect jack. I have repeated this more than once it is
always the same. Low latency kernel, jack is starting in RT.

In the same way that I do not know the internals of jack, I don't know the
internals of pulse. I am sure you know more than I do about both. But it
is hard to argue with experimental data.

-- 
Len Ovens
www.OvenWerks.net
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