[SOLVED] alsa/timidity doesn't recognize default device

[samuele]

In Debian 10, When I start timidity as alsa sequencer with a normal user, no problem at all. It works flawlessy.

Code: Select all

samuele@INSPIRON-17:~$ timidity -Os -iA
Requested buffer size 32768, fragment size 8192
ALSA pcm 'default' set buffer size 32768, period size 8192 bytes
TiMidity starting in ALSA server mode
Opening sequencer port: 128:0 128:1 128:2 128:3

When I switch to root user, it dosen't works anymore:

Code: Select all

root@INSPIRON-17:~# timidity -Os -iA
ALSA lib pcm_dmix.c:1108:(snd_pcm_dmix_open) unable to open slave
Can't open pcm device 'default'.
Couldn't open ALSA pcm device (`s')

It seems it cannot finde the "default" device. I know I can forcing it creating an ~/.asoundrc file or a global /etc/asound.conf, but the normal user dosen't need it. It seems it's accessing the global /usr/share/alsa/alsa.conf, while root dosen't.

So my question is: how i can fix that without writing a new config file? Is it possible to let root access the global file, or I'm missing something?

[samuele]

i think i found something.

According to /usr/share/alsa/alsa.conf, all conf from /etc/alsa/conf.d are loaded. There we have a 99-pulse.conf, linked to /usr/share/alsa/pulse-alsa.conf.
In this last file, pulse is set as default alsa device when pulseaudio is started.

So the reason tmidity it's working in the user' session is because it is using the pulse device.

The root user is not able to access pulseaudio, so there we are.. it's not working.

So a solution can be to enable root user to use pulse. Maybe starting as systemwide... (not so secure) or maybe allowing the root user in another way...

[CwF]

Code: Select all

# pulseaudio --start
W: [pulseaudio] main.c: This program is not intended to be run as root (unless --system is specified).
# pulseaudio --system
W: [pulseaudio] main.c: Running in system mode, but --disallow-exit not set.
W: [pulseaudio] main.c: Running in system mode, but --disallow-module-loading not set.
N: [pulseaudio] main.c: Running in system mode, forcibly disabling SHM mode.
N: [pulseaudio] main.c: Running in system mode, forcibly disabling exit idle time.
W: [pulseaudio] main.c: OK, so you are running PA in system mode. Please note that you most likely shouldn't be doing that.
W: [pulseaudio] main.c: If you do it nonetheless then it's your own fault if things don't work as expected.
W: [pulseaudio] main.c: Please read http://www.freedesktop.org/wiki/Software/PulseAudio/Documentation/User/WhatIsWrongWithSystemWide/ for an explanation why system mode is usually a bad idea.
W: [pulseaudio] authkey.c: Failed to open cookie file '/var/run/pulse/.config/pulse/cookie': No such file or directory
W: [pulseaudio] authkey.c: Failed to load authentication key '/var/run/pulse/.config/pulse/cookie': No such file or directory
W: [pulseaudio] authkey.c: Failed to open cookie file '/var/run/pulse/.pulse-cookie': No such file or directory
W: [pulseaudio] authkey.c: Failed to load authentication key '/var/run/pulse/.pulse-cookie': No such file or directory
W: [pulseaudio] protocol-native.c: Denied access to client with invalid authentication data.

[samuele]

I believe the real solution it's to change the way timidity daemon is started, changing it from system-wide to user, after pulseaudio is started, instead of changing pulseaudio.

timidity file is /etc/init.d/timidity. How i can do that? How can i change this scripts making it as a service in /usr/lib/systemd/user like pulseaudio.service and be sure at the same time that it spawns after pulseaudio? or maybe the correct solution involves changing permissions? i really don't know. Any idea?

[CwF]

My answer is to not use root.

[samuele]

yes... as i said i want to start it as a service...

[Head_on_a_Stick]

timidity file is /etc/init.d/timidity. How i can do that? How can i change this scripts making it as a service in /usr/lib/systemd/user like pulseaudio.service and be sure at the same time that it spawns after pulseaudio?

You don't need to change the service file at all, just call it in the ExecStart= line of a custom systemd user service with Requires=pulseaudio.service and After=pulseaudio.service in the [Unit] section. See also http://0pointer.de/blog/projects/system ... ins-3.html

EDIT: or just add the timidity command to ~/.profile (for console sessions) or ~/.xsessionrc (for graphical sessions).

[samuele]

timidity file is /etc/init.d/timidity. How i can do that? How can i change this scripts making it as a service in /usr/lib/systemd/user like pulseaudio.service and be sure at the same time that it spawns after pulseaudio?

You don't need to change the service file at all, just call it in the ExecStart= line of a custom systemd user service with Requires=pulseaudio.service and After=pulseaudio.service in the [Unit] section. See also http://0pointer.de/blog/projects/system ... ins-3.html

EDIT: or just add the timidity command to ~/.profile (for console sessions) or ~/.xsessionrc (for graphical sessions).

ok this is very useful, thank you!! And this works without breaking anything. Sadly i didn't waited for your answer and i configured pulseaudio as system-wide

I tested the system-wide version while waiting. So i post both the soultions here if some may need them.


The simplest and less invasive solution is the one you said: Just install all the base packages:

Code: Select all

sudo apt-get install timidity fluid-soundfont-gm

then create (with sudo) a systemd unit file, located under /usr/lib/systemd/user/timidity.service, with this content

Code: Select all

[Unit]
Description=Timidity
After=pulseaudio.service

[Service]
Type=simple
ExecStart=/usr/bin/timidity -Os -iA

[Install]
WantedBy=pulseaudio.service

now install and enable it

Code: Select all

systemctl --user enable timidity.service
systemctl --user start timidity.service

And it's done, started per-user.

The other solution, in order to get pulse/timidity to work as root system-wide, those are the steps:

To get it system-wide, follow the following steps (inspired by https://raven4.cz/wp/pulseaudio-in-system-wide-mode/)

first install base packages

Code: Select all

sudo apt-get install timidity timidity-daemon fluid-soundfont-gm

edit (with sudo) /etc/pulse/daemon.conf, search the row

Code: Select all

; system-instance = no

uncomment it and set it to yes

Code: Select all

system-instance = yes

now make a backup of the files /etc/pulse/system.pa and /etc/pulse/default.pa, just in case you want to rollback, then symlink default.pa as system.pa

Code: Select all

sudo mv /etc/pulse/system.pa /etc/pulse/system.pa.bak
sudo cp /etc/pulse/default.pa /etc/pulse/default.pa.bak
sudo ln -s /etc/pulse/default.pa /etc/pulse/system.pa

now edit (sudo) /etc/pulse/default.pa, find the row

Code: Select all

load-module module-native-protocol-unix

and change it this way

Code: Select all

load-module module-native-protocol-unix auth-group-enable=true auth-group=pulse-access socket=/tmp/pulse-socket

now edit (sudo) /etc/pulse/client.conf, find the row

Code: Select all

; default-server =

uncomment it and set it this way

Code: Select all

default-server = unix:/tmp/pulse-socket

now we need to add every user we want have access to pulseaudio in the account pulse-access. timidity will run as his own user, so we need to add it too. In my case i want the user root and my main user, samuele, so i'll do:

Code: Select all

usermod -a -G pulse-access root
usermod -a -G pulse-access samuele
usermod -a -G pulse-access timidity

now we need to create the custom pulseaudio.service file. so create a file in /etc/systemd/system/pulseaudio.service with this content

Code: Select all

[Unit]
Description=Pulseaudio

[Service]
User=root
Type=forking
ExecStart=/bin/pulseaudio --realtime --daemonize
Restart=always

[Install]
WantedBy=graphical.target

Now it's time to fix timidity.

Check if it's working with

Code: Select all

aconnect -lo | grep -i timidity

if not, start it

Code: Select all

sudo service timidity start

check again, if everything it's working, whe have a generated service file in /run/systemd/generator.late/timidity.service

copy it to /etc/systemd/system

Code: Select all

sudo cp /run/systemd/generator.late/timidity.service /etc/systemd/system/timidity.service

now edit it (sudo) and in the file beginning search for

Code: Select all

After=remote-fs.target

and change it this way

Code: Select all

After=remote-fs.target pulseaudio.service

In file ending add those two lines to make it installable

Code: Select all

[Install]
WantedBy=multi-user.target

Now it's time for cleaning. stop timidity and remove it from init.d

Code: Select all

sudo service timidity stop
sudo update-rc.d -f timidity remove

stop the per-user pulseaudio, disable it and clean your userdir config

Code: Select all

systemctl --user stop pulseaudio.socket
systemctl --user stop pulseaudio.service
systemctl --user disable pulseaudio.socket
systemctl --user disable pulseaudio.service
rm -Rf ~/.config/pulse/

now enable the new services

Code: Select all

sudo systemctl enable /etc/systemd/system/pulseaudio.service
sudo systemctl enable /etc/systemd/system/timidity.service

restart the machine aaaand.. it's done!