[pulseaudio-discuss] Some info on the RME Hammerfall DSP

[Daniel Chen]

[I don't know whether this was moderated or whether you're a
subscriber, so I added you.]

On Mon, Sep 27, 2010 at 7:52 AM, David Kastrup <dak at gnu.org> wrote:
>    amixer -D hw:DSP cget numid=23
>
> now displays
>
> numid=23,iface=CARD,name='Precise Pointer'
>  ; type=BOOLEAN,access=rw------,values=1
>  : values=on
>
> where the default is 'off'.  Which does not appear to disturb Jack.  But
> pulseaudio most certainly does not seem to like it, with tsched=1
> suffering much worse than tsched=0.
>
> Setting this to 'On' makes pulseaudio work worse with tsched=0, and
> apparently have no problems with tsched=1.

There are two places where this control can be set (i.e., the
"default" changed), via alsactl's init db or in the driver itself.
Because Maverick is in deep freeze, and because Lucid is in an even
deeper freeze (having been released months ago), the best thing to do
at this point is to file a bug using "ubuntu-bug alsa-base" so that
the appropriate mixer information can be uploaded to Launchpad, and a
patch can be generated for one of the above contexts.  Personally, the
former makes more sense and is less likely to cause regressions in the
short term.  The main thing to test then becomes confirming that jackd
works correctly with that setting.  After "sufficient" testing, the
driver could be updated.


> All this is rather crazy, and I have no idea where to report it such
> that a future version of Ubuntu will run out of the box.

There isn't an easy way to set everything up nicely for this
particular card yet.  The changes will touch alsa-lib and alsa-utils
(or possibly alsa-driver, the latter depending on which route above is
taken).


> Is there any way I can get Pulseaudio to set this particular control
> when opening the hw:DSP device?

Sure, one can hack the mixer profile paths to set it, but that isn't
the recommended way.  It should be done via alsactl init.

Best,
-Dan