Disable optical sound line on MacBook Pros

**Nightstalker** · 16-Nov-2020, 03:54

Each time I booted in openSUSE, the digital optical line was activated (output of red light from the mini jack port), so after some google searchs, I've found how to disable this with the help of ALSA:

Fire up a root shell and launch alsamixer(1)
Use the arrow keys to move around and when over S/PDIF press M to mute (if there's more than one S/PDIF lines cycle mute through each of those until this turns off the light)
Hit the Escape key - DO NOT CLOSE TERMINAL
Type `sudo alsactl store -f /var/lib/alsa/asound.state` - This will make it persist across reboots
Close the shell

**hcvv** · 16-Nov-2020, 04:25

A minor remark/question.

Why do you use sudo in #4 when you already fired up a root shell in #1?

**Nightstalker** · 18-Nov-2020, 01:50

Nice catch! Thanks

Its a typo, call to sudo(8) isn't needed

**Nightstalker** · 22-Nov-2020, 08:27

Unfortunately, calling alsamixer(1) from a root shell or with sudo(8) doesn't work anymore on openSUSE Tumbleweed (20201119 snapshot here) so as a workaround I've created the following .desktop file to autostart from your DE a call to alsactl(1):

Code:

alsactl --file ~/.config/asound.state store

Create with your favorite editor the alsarestore.desktop file:

Code:

vim ~/.config/autostart/alsarestore.desktop

with the following content:

Code:

[Desktop Entry]
Type=Application
Terminal=false
Name=alsarestore
Exec=bash -c 'sleep 15 ; alsactl --file ~/.config/asound.state restore'

**Nightstalker** · 25-Nov-2020, 04:29

Another cleaner way of disabling at boot the S/PDIF on MacBook Pros running Tumbleweed and globally is making systemd(1) handles this with a help of a new service and timer as by default alsa tries to restore /var/lib/alsa/asound.state before the sound card driver is entirely loaded by the kernel.

On a root shell:

1. Create a new systemd service "/etc/systemd/system/alsa-restore-delayed.service" with the following content after disabling the S/PDIF output (see my first message of this tread):

Code:

[Unit]
Description=Delayed Restore Sound Card State 
ConditionPathExists=!/etc/alsa/state-daemon.conf
ConditionPathExistsGlob=/dev/snd/control*
ConditionPathExists=/var/lib/alsa/asound.state

[Service]
Type=oneshot
ExecStart=-/usr/sbin/alsactl restore

2. Create a systemd timer "/etc/systemd/system/alsa-restore-delayed.timer" with the following content:

Code:

[Unit]
Description=Timer Delayed Restore Sound Card State

[Timer]
OnBootSec=30

3. Add the timer at multi-user.target:

Code:

systemctl add-wants multi-user.target alsa-restore-delayed.timer && systemctl daemon-reload

Credits goes to user laurent85

**karlmistelberger** · 25-Nov-2020, 12:39

Originally Posted by Nightstalker

Another cleaner way of disabling at boot the S/PDIF on MacBook Pros running Tumbleweed and globally is making systemd(1) handles this with a help of a new service and timer as by default alsa tries to restore /var/lib/alsa/asound.state before the sound card driver is entirely loaded by the kernel.

On a root shell:

1. Create a new systemd service "/etc/systemd/system/alsa-restore-delayed.service" with the following content after disabling the S/PDIF output (see my first message of this tread):

Code:

[Unit]
Description=Delayed Restore Sound Card State 
ConditionPathExists=!/etc/alsa/state-daemon.conf
ConditionPathExistsGlob=/dev/snd/control*
ConditionPathExists=/var/lib/alsa/asound.state

[Service]
Type=oneshot
ExecStart=-/usr/sbin/alsactl restore

2. Create a systemd timer "/etc/systemd/system/alsa-restore-delayed.timer" with the following content:

Code:

[Unit]
Description=Timer Delayed Restore Sound Card State

[Timer]
OnBootSec=30

3. Add the timer at multi-user.target:

Code:

systemctl add-wants multi-user.target alsa-restore-delayed.timer && systemctl daemon-reload

Credits goes to user laurent85

openSUSE has its own alsa services:

Code:

erlangen:~ # systemctl list-unit-files 'alsa*'               
UNIT FILE            STATE  VENDOR PRESET
alsa-restore.service static -            
alsa-state.service   static -            
alsasound.service    alias  -            

3 unit files listed. 
erlangen:~ #

openSUSE has target:

Code:

erlangen:~ # systemctl list-dependencies timers.target             
timers.target 
● ├─backup-home.timer 
● ├─backup-rpmdb.timer 
● ├─backup-sysconfig.timer 
● ├─btrfs-balance.timer 
● ├─btrfs-defrag.timer 
● ├─btrfs-scrub.timer 
● ├─btrfs-trim.timer 
● ├─fstrim.timer 
● ├─logrotate.timer 
● ├─mandb.timer 
● ├─mlocate.timer 
● ├─packagekit-background.timer 
● ├─snapper-cleanup.timer 
● ├─snapper-timeline.timer 
● └─systemd-tmpfiles-clean.timer 
erlangen:~ #

Timers have an install section:

Code:

[Install] 
WantedBy=timers.target

You may try to use vendor versions of alsa services.

**Nightstalker** · 26-Nov-2020, 07:10

Thanks for your inputs. However none of the default timer and systemd services bundled with Tumbleweed works with these laptops.
The S/PDIF is always active despite custom settings set with alsamixer(1) and saved on /var/lib/alsa/asound.state.

At first view, with none of the workarounds I've made, leaving Tumbleweed doing its stuff, /var/lib/alsa/asound.state is reseted at each boot no matter what custom settings are saved with `alsactl store` on /var/lib/alsa/asound.state.
From logs, this shows alsa is trying to apply settings before the sound card driver is fully loaded, thus overwriting custom /var/lib/alsa/asound.state with a new one.

With Leap 15.2, it just works whereas it's not with Tumbleweed snapshots I've tested and actually use, so the last workaround I've posted actually works on all of the MacBook Pros I resurrected thanks to openSUSE

**karlmistelberger** · 26-Nov-2020, 10:52

Originally Posted by Nightstalker

At first view, with none of the workarounds I've made, leaving Tumbleweed doing its stuff, /var/lib/alsa/asound.state is reseted at each boot no matter what custom settings are saved with `alsactl store` on /var/lib/alsa/asound.state. From logs, this shows alsa is trying to apply settings before the sound card driver is fully loaded, thus overwriting custom /var/lib/alsa/asound.state with a new one.

Thanks for the feedback! Are you sure:

Code:

erlangen:~ # journalctl -b -1 -u alsa-restore.service  
-- Logs begin at Sat 2020-11-14 06:05:06 CET, end at Thu 2020-11-26 18:44:19 CET. -- 
Nov 25 21:05:16 erlangen systemd[1]: Starting Save/Restore Sound Card State... 
Nov 25 21:05:17 erlangen systemd[1]: Finished Save/Restore Sound Card State. 
Nov 26 18:42:00 erlangen systemd[1]: Stopping Save/Restore Sound Card State... 
Nov 26 18:42:00 erlangen systemd[1]: alsa-restore.service: Succeeded. 
Nov 26 18:42:00 erlangen systemd[1]: Stopped Save/Restore Sound Card State. 
erlangen:~ # systemctl status alsa-restore.service 
● alsa-restore.service - Save/Restore Sound Card State 
     Loaded: loaded (/usr/lib/systemd/system/alsa-restore.service; static) 
     Active: active (exited) since Thu 2020-11-26 18:42:37 CET; 5min ago 
    Process: 763 ExecStart=/usr/sbin/alsactl restore (code=exited, status=0/SUCCESS) 
   Main PID: 763 (code=exited, status=0/SUCCESS) 

Nov 26 18:42:37 erlangen systemd[1]: Starting Save/Restore Sound Card State... 
Nov 26 18:42:37 erlangen systemd[1]: Finished Save/Restore Sound Card State. 
erlangen:~ #

Did you check conditions?

Code:

erlangen:~ # systemctl cat alsa-restore.service    
# /usr/lib/systemd/system/alsa-restore.service
# 
# Note that two different ALSA card state management schemes exist and they 
# can be switched using a file exist check - /etc/alsa/state-daemon.conf . 
# 

[Unit] 
Description=Save/Restore Sound Card State 
ConditionPathExists=!/etc/alsa/state-daemon.conf 
ConditionPathExistsGlob=/dev/snd/control* 
ConditionPathExists=/var/lib/alsa/asound.state 

[Service] 
Type=oneshot 
RemainAfterExit=true 
ExecStart=-/usr/sbin/alsactl restore 
ExecStop=-/usr/sbin/alsactl store 
erlangen:~ #

**Nightstalker** · 26-Nov-2020, 19:16

Originally Posted by karlmistelberger

Thanks for the feedback! Are you sure:

You're welcome

Yes (do note on the following output I have disabled alsa-restore.service but still having the same output if /etc/alsa/state-daemon.conf is there and this service is enabled):

Code:

root@raiatea:/home/matt # journalctl -b -1 -u alsa-restore.service 
-- Logs begin at Sun 2020-11-22 13:30:29 CET, end at Fri 2020-11-27 02:48:05 CET. --
nov. 26 15:46:14 raiatea systemd[1]: Starting Save/Restore Sound Card State...
nov. 26 15:46:14 raiatea systemd[1]: Finished Save/Restore Sound Card State.
nov. 27 02:10:49 raiatea.local systemd[1]: Stopping Save/Restore Sound Card State...
nov. 27 02:10:49 raiatea.local systemd[1]: alsa-restore.service: Succeeded.
nov. 27 02:10:49 raiatea.local systemd[1]: Stopped Save/Restore Sound Card State.
root@raiatea:/home/matt # systemctl status alsa-restore.service    
● alsa-restore.service - Save/Restore Sound Card State
     Loaded: loaded (/usr/lib/systemd/system/alsa-restore.service; static)
     Active: inactive (dead)
  Condition: start condition failed at Fri 2020-11-27 02:11:07 CET; 38min ago
             └─ ConditionPathExistsGlob=/dev/snd/control* was not met

nov. 27 02:11:07 raiatea systemd[1]: Condition check resulted in Save/Restore Sound Card State being skipped.
root@raiatea:/home/matt #

Originally Posted by karlmistelberger

Did you check conditions?

Also yes:

Code:

root@raiatea:/home/matt # systemctl cat alsa-restore.service
# /usr/lib/systemd/system/alsa-restore.service
#
# Note that two different ALSA card state management schemes exist and they
# can be switched using a file exist check - /etc/alsa/state-daemon.conf .
#

[Unit]
Description=Save/Restore Sound Card State
ConditionPathExists=!/etc/alsa/state-daemon.conf
ConditionPathExistsGlob=/dev/snd/control*
ConditionPathExists=/var/lib/alsa/asound.state

[Service]
Type=oneshot
RemainAfterExit=true
ExecStart=-/usr/sbin/alsactl restore
ExecStop=-/usr/sbin/alsactl store
root@raiatea:/home/matt #

Why one of alsa-restore.service's condition is not met puzzle me and lead me to think that the sound card driver isn't fully loaded before the service is run. On Leap 15.2 no such problem after muting the S/PDIF in alsamixer(1).

**karlmistelberger** · 27-Nov-2020, 01:13

Originally Posted by Nightstalker

Why one of alsa-restore.service's condition is not met puzzle me and lead me to think that the sound card driver isn't fully loaded before the service is run. On Leap 15.2 no such problem after muting the S/PDIF in alsamixer(1).

What are yours:

Code:

erlangen:~ # systemctl list-dependencies alsa-restore.service 
alsa-restore.service 
● ├─system.slice 
● └─sysinit.target 
●   ├─dev-hugepages.mount 
●   ├─dev-mqueue.mount 
●   ├─dracut-shutdown.service 
●   ├─haveged.service 
●   ├─kmod-static-nodes.service 
●   ├─plymouth-read-write.service 
●   ├─plymouth-start.service 
●   ├─proc-sys-fs-binfmt_misc.automount 
●   ├─sys-fs-fuse-connections.mount 
●   ├─sys-kernel-config.mount 
●   ├─sys-kernel-debug.mount 
●   ├─sys-kernel-tracing.mount 
●   ├─systemd-ask-password-console.path 
●   ├─systemd-binfmt.service 
●   ├─systemd-boot-system-token.service 
●   ├─systemd-firstboot.service 
●   ├─systemd-hwdb-update.service 
●   ├─systemd-journal-catalog-update.service 
●   ├─systemd-journal-flush.service 
●   ├─systemd-journald.service 
●   ├─systemd-machine-id-commit.service 
●   ├─systemd-modules-load.service 
●   ├─systemd-random-seed.service 
●   ├─systemd-sysctl.service 
●   ├─systemd-sysusers.service 
●   ├─systemd-tmpfiles-setup-dev.service 
●   ├─systemd-tmpfiles-setup.service 
●   ├─systemd-udev-trigger.service 
●   ├─systemd-udevd.service 
●   ├─systemd-update-done.service 
●   ├─systemd-update-utmp.service 
●   ├─cryptsetup.target 
●   ├─local-fs.target 
●   │ ├─-.mount 
●   │ ├─\x2esnapshots.mount 
●   │ ├─boot-efi.mount 
●   │ ├─boot-grub2-i386\x2dpc.mount 
●   │ ├─boot-grub2-x86_64\x2defi.mount 
●   │ ├─home.mount 
●   │ ├─home\x2dSSD.mount 
●   │ ├─opt.mount 
●   │ ├─root.mount 
●   │ ├─srv.mount 
●   │ ├─systemd-remount-fs.service 
●   │ ├─tmp.mount 
●   │ ├─usr-local.mount 
●   │ ├─var-lock.mount 
●   │ ├─var-run.mount 
●   │ └─var.mount 
●   └─swap.target 
erlangen:~ #