ALSA on gentoo (without udev, custom configuration)

[stefan11111]

I am using gentoo and trying to only use a static /dev. I Only use alsa for sound, no pulseaudio or anything like that. If I am using udev, alsa works perfectly fine, even if I then stop udev. I I don't use udev, alsa won't work: ALSA lib /var/tmp/portage/media-libs/alsa-lib-1.2.8-r1/work/alsa-lib-1.2.8/src/confmisc.c:855(parse_card) cannot find card '0'

[perexg]

Static device nodes are supported only when the kernel is compiled with CONFIG_SND_DYNAMIC_MINORS=n. Note that some drivers will force the dynamic minor number allocation and almost all platforms including embedded, are using udev nowadays.

[stefan11111]

Thanks for responding. I have recompiled my kernel with this option and I still have this problem. It appears that udev also populates /sys. When not using udev, the folder /sys/class/sound does not exist and I cannot create it to make the proper symlinks.

[perexg]

The standard alsa-lib functions do not require sysfs (/sys tree). Only UCM code may use this subsystem for additional checks. It looks like another problem (minor numbers etc.). You may use strace tool to check which system calls fail when the ALSA card is probed.

[stefan11111]

I have used strace as instructed. Here is the output of strace speaker-test: https://pastebin.com/6fY2WygZ

I may need to use mknod to manually populate /dev, but I am not sure how.

[perexg]

Something like:

mkdir /dev/snd
mknod -m 660 /dev/snd/controlC0 c 116 0
mknod -m 660 /dev/snd/pcmC0D0p c 116 16
mknod -m 660 /dev/snd/timer c 116 33
chown root:audio /dev/snd/*

The full list of minors is here: https://github.com/torvalds/linux/blob/master/include/sound/minors.h

[stefan11111]

I have made a screenshot of all the files that udev loads into /dev and used mknod like in the example above.

stefan@GentooPC ~ $ ls -lah /dev/snd
total 0
drwxr-xr-x  2 root root      320 Jan 28 21:19 .
drwxr-xr-x 17 root root     4.2K Jan 28 21:18 ..
crw-rw----  1 root audio 116,  0 Jan 28 21:19 controlC0
crw-rw----  1 root audio 116, 32 Jan 28 21:19 controlC1
crw-rw----  1 root audio 116, 64 Jan 28 21:19 controlC2
crw-rw----  1 root audio 116, 36 Jan 28 21:19 hwC1D0
crw-rw----  1 root audio 116, 68 Jan 28 21:19 hwC2D0
crw-rw----  1 root audio 116, 24 Jan 28 21:19 pcmC0D0c
crw-rw----  1 root audio 116, 16 Jan 28 21:19 pcmC0D0p
crw-rw----  1 root audio 116, 56 Jan 28 21:19 pcmC1D0c
crw-rw----  1 root audio 116, 48 Jan 28 21:19 pcmC1D0p
crw-rw----  1 root audio 116, 49 Jan 28 21:19 pcmC1D1p
crw-rw----  1 root audio 116, 58 Jan 28 21:19 pcmC1D2c
crw-rw----  1 root audio 116, 83 Jan 28 21:19 pcmC2D3p
crw-rw----  1 root audio 116,  1 Jan 28 21:18 seq
crw-rw----  1 root audio 116, 33 Jan 28 21:18 timer
stefan@GentooPC ~ $ aplay -L
null
    Discard all samples (playback) or generate zero samples (capture)
stefan@GentooPC ~ $ aplay -l
aplay: device_list:274: no soundcards found...
stefan@GentooPC ~ $

Using strace, I still see messages like this: openat(AT_FDCWD, "/dev/snd/controlC0", O_RDONLY|O_CLOEXEC) = -1 ENODEV (No such device)

even though /dev/snd/controlC0 clearly exists

[perexg]

Do you have the sound driver active ? (cat /proc/asound/cards)

[stefan11111]

stefan@GentooPC ~ $ cat /proc/asound/cards
--- no soundcards ---

Guess not, though I have never installed a sound driver as an out of tree module or something.

[perexg]

You should select the ALSA sound driver for your hardware in the kernel config.

[stefan11111]

I have build my kernel using genkernel and I have just changed the options needed for CONFIG_SND_DYNAMIC_MINORS=n. I will try to build all the sound drivers directly into the kernel. If that doesn't fix it, I'll do a manual kernel config. Wish me luck.

[perexg]

In my first reply, I noted that some drivers require the dynamic minor number allocations. You should check the kernel's CONFIGSND configuration options, if they are enabled before the kernel compilation.

[perexg]

It may be eventually possible to use the dynamic minors - but a custom script which will create the device nodes (mknod) from /proc/asound/devices file must be written. The first number is the minor.

[stefan11111]

I do not really use a sound card. I have a razer headset that is connected via usb and I do not use openrazer.

Both /proc/asound/cards and /proc/asound/devices are empty

[perexg]

It's probably an USB sound card built-in to the headset. Enable ALSA USB sound driver.

[stefan11111]

I have recompiled my kernel with the alsa sound module. This is the output of cat /proc/asound/cards:

stefan@GentooPC ~ $ cat /proc/asound/cards
 0 [PCH            ]: HDA-Intel - HDA Intel PCH
                      HDA Intel PCH at 0xf7140000 irq 132
 1 [NVidia         ]: HDA-Intel - HDA NVidia
                      HDA NVidia at 0xf7080000 irq 17
 2 [Ultimate       ]: USB-Audio - Razer Kraken Ultimate
                      Razer Razer Kraken Ultimate at usb-0000:00:14.0-12, full speed

This is the output of cat ~/.asoundrc:

stefan@GentooPC ~ $ cat ~/.asoundrc
defaults.pcm.card 2
defaults.ctl.card 2

This is the output of speaker-test:

stefan@GentooPC ~ $ speaker-test

speaker-test 1.2.8

Playback device is default
Stream parameters are 48000Hz, S16_LE, 1 channels
Using 16 octaves of pink noise
ALSA lib /var/tmp/portage/media-libs/alsa-lib-1.2.8-r1/work/alsa-lib-1.2.8/src/pcm/pcm_dmix.c:999:(snd_pcm_dmix_open) unable to open slave
Playback open error: -13,Permission denied

This is the output of aplay -l:

stefan@GentooPC ~ $ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: PCH [HDA Intel PCH], device 0: ALC892 Analog [ALC892 Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: PCH [HDA Intel PCH], device 1: ALC892 Digital [ALC892 Digital]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: NVidia [HDA NVidia], device 3: Generic Digital [Generic Digital]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 2: Ultimate [Razer Kraken Ultimate], device 0: USB Audio [USB Audio]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

I have written 2 scripts to load the necessary modules and make the necessary /dev files:

stefan@GentooPC ~ $ cat mknod_snd
mkdir /dev/snd
mknod -m 660 /dev/snd/controlC0 c 116 0
mknod -m 660 /dev/snd/pcmC0D0p c 116 16
mknod -m 660 /dev/snd/timer c 116 33
mknod -m 660 /dev/snd/seq c 166 1
mknod -m 660 /dev/snd/controlC2 c 116 64
mknod -m 660 /dev/snd/controlC1 c 116 32
mknod -m 660 /dev/snd/pcmC0D0c c 116 24
mknod -m 660 /dev/snd/hwC1D0 c 116 36
mknod -m 660 /dev/snd/hwC2D0 c 116 68
mknod -m 660 /dev/snd/pcmC1D0c c 116 56
mknod -m 660 /dev/snd/pcmC1D0p c 116 48
mknod -m 660 /dev/snd/pcmC1D1p c 116 49
mknod -m 660 /dev/snd/pcmC1D2c c 116 58
mknod -m 660 /dev/snd/pcmC2D3p c 116 83
chown root:audio /dev/snd/*

stefan@GentooPC ~ $ cat sound_modules
modprobe snd_rawmidi
modprobe snd_usbmidi_lib
modprobe snd_hda_core
modprobe snd_hda_codec
modprobe snd_hda_codec_generic
modprobe snd_hda_intel
modprobe snd_hda_codec_realtek
modprobe ledtrig_audio
modprobe pcspkr
modprobe snd_usb_audio
modprobe snd_hwdep
modprobe snd_intel_sdw_acpi
modprobe snd_intel_dspcfg
modprobe snd_usb_audio
modprobe mc
modprobe snd
modprobe soundcore
modprobe snd_seq_device
modprobe snd_timer
modprobe snd_pcm

Here is the output of strace speaker-test:

https://pastebin.com/brjkbNDR

[perexg]

openat(AT_FDCWD, "/dev/snd/pcmC2D0p", O_RDWR|O_NONBLOCK|O_CLOEXEC) = -1 EACCES (Permission denied)

Check if the user is in the audio group.

[stefan11111]

This is the output of groups:

stefan@GentooPC ~ $ groups
tty wheel audio video input users stefan

My user seems to be in the audio group. I have just tested running speaker-test and youtube on librewolf with root privileges and it works properly. I would call this progress.

[perexg]

Check the other permission related setup - /dev/snd directory permissions, SELinux or so... It's out of scope of support for the audio. Ask on gentoo forums.

[stefan11111]

I will do so. Thanks for helping me so far.

One more thing. After running chgrp audio /dev/snd speaker-test runs without errors, but it still makes no sound.

[stefan11111]

@perexg I have fixed the issue. I will post it here for anyone who will encounter this issue. I wrote a script to make all the necessary nodes and load all the necessary modules:

mkdir /dev/snd
mknod -m 660 /dev/snd/controlC0 c 116 0
mknod -m 660 /dev/snd/pcmC0D0p c 116 16
mknod -m 660 /dev/snd/timer c 116 33
mknod -m 660 /dev/snd/seq c 166 1
mknod -m 660 /dev/snd/controlC2 c 116 64
mknod -m 660 /dev/snd/controlC1 c 116 32
mknod -m 660 /dev/snd/pcmC0D0c c 116 24
mknod -m 660 /dev/snd/hwC1D0 c 116 36
mknod -m 660 /dev/snd/hwC2D0 c 116 68
mknod -m 660 /dev/snd/pcmC1D0c c 116 56
mknod -m 660 /dev/snd/pcmC1D0p c 116 48
mknod -m 660 /dev/snd/pcmC1D1p c 116 49
mknod -m 660 /dev/snd/pcmC1D2c c 116 58
mknod -m 660 /dev/snd/pcmC2D3p c 116 83
chown root:audio /dev/snd/*
chown root:audio /dev/snd
modprobe snd_rawmidi
modprobe snd_usbmidi_lib
modprobe snd_hda_core
modprobe snd_hda_codec
modprobe snd_hda_codec_generic
modprobe snd_hda_intel
modprobe snd_hda_codec_realtek
modprobe ledtrig_audio
modprobe pcspkr
modprobe snd_usb_audio
modprobe snd_hwdep
modprobe snd_intel_sdw_acpi
modprobe snd_intel_dspcfg
modprobe snd_usb_audio
modprobe mc
modprobe snd
modprobe soundcore
modprobe snd_seq_device
modprobe snd_timer
modprobe snd_pcm
chmod -R a+rw /dev/snd

for convenience, I added this to my .xinitrc:

#!/bin/sh

slstatus &
xcompmgr &
/usr/bin/feh --bg-fill '/home/stefan/images/wallpapers/2.jpg' &
xset -dpms &
xset s off &
rdo ntpd &
qbittorrent-nox &
rdo curl https://raw.githubusercontent.com/StevenBlack/hosts/master/hosts > /etc/hosts &
rdo mount -a &
#make /dev nodes
mkdir /dev/snd
rdo mknod -m 660 /dev/snd/controlC0 c 116 0
rdo mknod -m 660 /dev/snd/pcmC0D0p c 116 16
rdo mknod -m 660 /dev/snd/timer c 116 33
rdo mknod -m 660 /dev/snd/seq c 166 1
rdo mknod -m 660 /dev/snd/controlC2 c 116 64
rdo mknod -m 660 /dev/snd/controlC1 c 116 32
rdo mknod -m 660 /dev/snd/pcmC0D0c c 116 24
rdo mknod -m 660 /dev/snd/hwC1D0 c 116 36
rdo mknod -m 660 /dev/snd/hwC2D0 c 116 68
rdo mknod -m 660 /dev/snd/pcmC1D0c c 116 56
rdo mknod -m 660 /dev/snd/pcmC1D0p c 116 48
rdo mknod -m 660 /dev/snd/pcmC1D1p c 116 49
rdo mknod -m 660 /dev/snd/pcmC1D2c c 116 58
rdo mknod -m 660 /dev/snd/pcmC2D3p c 116 83
rdo chown root:audio /dev/snd/*
rdo chown root:audio /dev/snd
#load kernel modules
rdo modprobe snd_rawmidi
rdo modprobe snd_usbmidi_lib
rdo modprobe snd_hda_core
rdo modprobe snd_hda_codec
rdo modprobe snd_hda_codec_generic
rdo modprobe snd_hda_intel
rdo modprobe snd_hda_codec_realtek
rdo modprobe ledtrig_audio
rdo modprobe pcspkr
rdo modprobe snd_usb_audio
rdo modprobe snd_hwdep
rdo modprobe snd_intel_sdw_acpi
rdo modprobe snd_intel_dspcfg
rdo modprobe snd_usb_audio
rdo modprobe mc
rdo modprobe snd
rdo modprobe soundcore
rdo modprobe snd_seq_device
rdo modprobe snd_timer
rdo modprobe snd_pcm
#set permissions
rdo chmod -R a+rw /dev/snd
#exec dbus-launch --exit-with-session dwm
exec dwm

rdo is a less bloated alternative to doas. All it does in this context is execute those commands as root. This line seems to have fixed it: rdo chmod -R a+rw /dev/snd I don't know if this is the best way to solve this, but it works. I would like some feedback.

Here is my .asoundrc:

defaults.pcm.card 2
defaults.ctl.card 2