udev script does not start when event happen

Question

I was annoyed that every time I connect my hdmi cable I need to manually change the sound setting.

I started looking into udev rules, what I came out with are these two files:

/etc/udev/rules.d/99-hdmi_sound.rules

SUBSYSTEM=="drm", RUN+="/lib/udev/hdmi_sound_toggle.sh"

/lib/udev/hdmi_sound_toggle.sh:

#!/bin/bash

HDMI_STATUS=`cat /sys/class/drm/card0/*HDMI*/status`
if [ $HDMI_STATUS = "connected" ]
then
    sudo -u root pactl set-card-profile 0 output:hdmi-stereo
else
    sudo -u root pactl set-card-profile 0 output:analog-stereo
fi

When I'm running hdmi_sound_toggle.sh in the terminal, it works. It does not auto-run, though.

What am I doing wrong?

Here is Set HDMI sound output automatically on connect/disconnect and Switching to HDMI Audio when HDMI is plugged into a laptop (14.04) — Lety, Oct 05 '14 at 22:15
I used those answers to get to my current state. Again, because the script works when I run it from the terminal, I'm pretty sure that the problem is in the udev rule. — guy, Oct 06 '14 at 06:29
It can be related to user who runs script. Take a look at Set HDMI sound output automatically on connect/disconnect pactl is runned with sudo -u $user. When you run this script manually, script run with your privilege, while when it auto-run (I guess) user should be root. — Lety, Oct 06 '14 at 10:59

score 0 · Answer 1 · answered Oct 15 '14 at 14:01

0

Have you tried reloading udev? It should recognise new rules automatically, but maybe it didn't...

sudo udevadm control --reload-rules ; sudo udevadm trigger

answered Oct 15 '14 at 14:01

Frederick Nord

549
5
9

I tried.. doesn't work – guy Oct 18 '14 at 09:59

user.dz · Answer 2 · 2014-10-26T09:00:16.213

0

Try rename it to 99-hdmi_sound.rules (with 2 digits only)

& use RUN instead and omit ACTION

SUBSYSTEM=="drm", RUN+="/lib/udev/hdmi_sound_toggle.sh"

It could be an environment problem (not same user, or undeclared env variables). Try adding some echo or touch commands to trace your script. Example:
```
echo `date --rfc-3339='ns'` START >> /home/<your-username>/Desktop/udev_test_log.txt
```
Put one in beginning, end, inside if, else ...

edited Oct 26 '14 at 09:00

answered Oct 24 '14 at 13:55

user.dz

48,105

Tried, doesn't work... updated the question – guy Oct 26 '14 at 07:42
ok, the rule actually working. the pactl cmd gives the error: Connection failure: Connection refused pa_context_connect() failed: Connection refused – guy Oct 26 '14 at 13:27
@guy, try sudo -u yourusername pactl ... – user.dz Oct 26 '14 at 14:00
tried... the error changed to Failure: No such entity the updated line: sudo -u guy pactl set-card-profile 0 output:hdmi-stereo 2>> /home/guy/Desktop/udev_then_log.txt. just checked - still work when I call the script from terminal – guy Oct 26 '14 at 14:17
sorry, double checked and it doesn't work manually, I will go over the steps and tell you when it stopped to work. – guy Oct 26 '14 at 14:27
ok, still working manually. didn't work because of writing the log there was needed root permission (tried without writing the log and worked). – guy Oct 26 '14 at 14:31
Does it work if you switch to root, su - then run it? – user.dz Oct 26 '14 at 14:35
yes, when I run from terminal after changing to root user – guy Oct 26 '14 at 21:02

udev script does not start when event happen

2 Answers2