[PlanetCCRMA] Pulseaudio and qjackctl

Simon Fielding s.fielding at wmcce.org
Thu May 7 02:48:17 PDT 2009

On Wed, 2009-05-06 at 14:58 -0700, Jeff Sandys wrote:
> I am testing Fedora 11, and I got qjackctl to work fine, but I think the
> configuration isn't right.  Here is the part of the note I posted to Fedora
> Forums:  I saw that Fernando weighed in on the Pulseaudio ALSA debate.
> I installed qjackctl on a Live-Preview-XFCE-i686 usb with persistence.
> In the qjackctl connect panel there were no audio output or input ports
> until I installed pulseaudio-module-jack and alsa-plugins-jack per Harald
> Hoyer's Pulseaudio and Jackd tips, (jack-audio-connection-kit was installed
> with qjackctl).
> http://www.harald-hoyer.de/linux/pulseaudio-and-jackd
> I added "liveuser" to pulse-rt and jackuser and noticed that
> /etc/security/limits.conf already had jackuser and pulse-rt added.
> Should pulseaudio-module-jack and/or alsa-plugins-jack be a dependency of
> qjackctl?
> I couldn't get my usb MIDI keyboard working, there were no midi or alsa
> output or input ports in qjackctl connect, and jack complained about not
> finding an ALSA midi seqencer when it started, until i did a modprobe
> snd-seq-oss. What is the default /dev/sequencer?
> Should modprode snd-seq-oss (or equivelent) be part of the standard
> distribution?
> After that qjackctl ran fine, I didn't have to stop pulseaudio to start jack
> or use any of the other suggestions in Harald's tips. I pounded on zyn for a
> while with jackd -R -r44100 -p250 -n2 with no xruns and about 10% usage.
> The XFCE panel volume control lets you select between Pulseaudio and the
> audio card, I had to switch to the card and set the PCM to 100% to get
> sound. This is a nice feature.
> What is the proper was to set up midi with jack so that the midi connectiosn
> show up on the MIDI tab instead of the ALSA tab?  
> Any other pointers to the correct modern linux audio setup is appreciated.
> Thanks,
> Jeff Sandys

I've been testing F11 a bit too - I found the following info
in /etc/modprobe.d/dist-oss.conf

# OSS Sound Support
# This has been disabled in F11 onwards because it can interfere with the
# PulseAudio sound service (a legacy OSS application can prevent PulseAudio
# applications from playing sound by preventing PulseAudio from (re-)opening
# the sound device). To re-enable support, uncomment the following line:
# install snd-pcm /sbin/modprobe --ignore-install snd-pcm && /sbin/modprobe snd-pcm-oss && /sbin/modprobe snd-seq-device && /sbin/modprobe snd-seq-oss

You may not want or need full OSS support so you could just add a single
modprobe for the sequencer which is what I did - ALSA and JACK midi tabs
both worked fine after that.


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