From: James Harkins <jamshark70@zoho.com>
To: "linux-audio-user" <linux-audio-user@lists.linuxaudio.org>
Subject: [LAU] How to recover from a JACK freeze?
Message-ID: <15df368d100.cbae553a56821.8435360232489998174@zoho.com>
Content-Type: text/plain; charset="UTF-8"

Hi, been inactive for a while.

I just up/cross-graded to Ubuntu Studio 16.04 -- very much enjoying it so far! I'm getting better USB audio performance than I could ever manage under plain Ubuntu (provided WiFi is off, but I can live with that for shows).

One problem that the upgrade didn't solve is that sometimes jackd gets stuck and it can't be killed.

Initial symptom: No audio, in or out.

Secondary symptom: In qjackctl, the CPU usage number is frozen -- never changes.

At that point:

$ ps x | grep jackd
3140 ? SLsl 0:16 /usr/bin/jackd -dalsa -r44100 -p1024 -n2 -D -Chw:Set,0 -Phw:Set
4458 pts/1 S+ 0:00 grep --color=auto jackd
$ kill -9 3140
$ ps x | grep jackd
3140 ? SLsl 0:16 /usr/bin/jackd -dalsa -r44100 -p1024 -n2 -D -Chw:Set,0 -Phw:Set
4460 pts/1 S+ 0:00 grep --color=auto jackd

"kill -9" has no effect.

"sudo kill -9" has no effect.

If I reboot, it takes several minutes for the system to shut down -- i.e., jackd is even preventing a clean shutdown.

So, the question: How do I regain control when this happens? (Ideally, without having to close everything.)

Pretty sure I've seen the same thing a few times, and the solution has been to reload the sound card driver. Here's my script to do that:

[kjetil@localhost ~]$ more bin/startdelta.sh

#!/bin/sh

fuser -fv /dev/snd/* /dev/dsp*

/home/kjetil/bin/removealsa.sh # see below

sleep 1

/home/kjetil/bin/alsasound start # ccrma dist script

modprobe snd-ice1712 # change to your sound card

#modprobe snd-hda-intel

modprobe snd-seq

chmod 777 /dev/snd/seq

alsactl restore 0

fuser -fv /dev/snd/* /dev/dsp*

[kjetil@localhost ~]$ more bin/removealsa.sh

#!/bin/sh

killall -9 pulseaudio

rmmod snd_hda_codec_atihdmi snd_hda_codec snd_hwdep snd_pcm snd_timer snd soundcore snd_page_alloc

rmmod snd_seq snd_timer snd_seq_device snd_seq_dummy snd-ice1712 snd_ice17xx_ak4xxx snd_ak4xxx_adda snd_hda_intel snd_cs8427 snd_hda_codec snd_ac97_codec snd_hwdep snd_seq snd_pcm ac97_bus snd_i2c snd_mpu401_uart snd_rawmidi snd_seq_device snd_timer snd soundcore snd_page_alloc

sleep 1

rmmod snd_hda_codec_atihdmi snd_hda_codec snd_hwdep snd_pcm snd_timer snd soundcore snd_page_alloc

rmmod snd_seq_midi,snd_seq_dummy,snd_ice1712,snd_ak4xxx_adda,snd_cs8427,snd_ac97_codec,snd_seq,snd_pcm,snd_timer,snd_i2c,snd_mpu401_uart,snd_rawmidi,snd_seq_device

rmmod snd_seq_midi,snd_seq,snd_timer,snd_rawmidi,snd_seq_device

rmmod snd_seq_midi_event snd-seq-midi snd-seq snd-timer snd-rawmidi snd-seq-device

rmmod snd_seq_oss snd_seq_midi_event snd_pcm_oss snd_seq snd_seq_device snd_pcm snd_timer snd_page_alloc snd_mixer_oss

rmmod snd_hda_codec_realtek snd_hda_codec_via snd_hda_codec snd_hwdep snd_pcm snd_timer

rmmod snd_hda_codec snd_hwdep snd_pcm snd_timer

rmmod snd_via82xx snd_hda_codec snd_hwdep snd_ac97_codec snd_mpu401_uart snd_rawmidi snd_seq_device snd_pcm snd_timer snd_page_alloc soundcore

rmmod snd