Dear Maintainer,

There are repeated errors in journald to this effect:

org_kde_powerdevil: Exception in function i2c_all_relevant_i2c_buses_rw:
status=EACCES(-13): Permission denied
org_kde_powerdevil:  libddcutil requires RW access to all /dev/i2c devices that
might be used for DDC.
org_kde_powerdevil: Caused by:
org_kde_powerdevil:  Exception in function i2c_open_bus_basic:
status=EACCES(-13): Permission denied
org_kde_powerdevil:  Open failed for /dev/i2c-0, errno=EACCES(-13): Permission
denied in file i2c_bus_cor>

I understand from my brief research that Debian sets /dev/i2c* root ownership,
which breaks non-privileged processes trying to access it. From
https://www.kubuntuforums.net/forum/current-supported-
releases/kubuntu-26-04/692450-trying-to-solve-kde-plasma-power-management-
powerdevil-configuration-bug%E2%80%A6 , it seems that udev rules or relaxing
permissions or ownership quickly solves the issue.

However, before adding exceptions, I'm wondering whether Debian can ship with a
recommended udev file or some other workaround.

Le mercredi 24 juin 2026, 11:10:31 heure d’été d’Europe centrale Borden a écrit :

Hi,

thanks for your bug report.
I cannot reproduce this myself.

May I ask for which device you’re running Debian on to get a bit more context ?

Would you mind pasting surrounding logs from org_kde_powerdevil ?


Thanks & happy hacking,
--
Aurélien

Le mercredi 24 juin 2026, 11:10:31 heure d’été d’Europe centrale Borden a écrit :

Hi,

thanks for your bug report.
I cannot reproduce this myself.

May I ask for which device you’re running Debian on to get a bit more context ?

Would you mind pasting surrounding logs from org_kde_powerdevil ?


Thanks & happy hacking,
--
Aurélien

Hi,

I had the same issue (Debian testing with KDE Plasma).

I found a workaround after reading those links :

https://discuss.cachyos.org/t/powerdevil-related-errors-when-trying-to-access-i2c-error-eacces-13/10233

and

https://wiki.archlinux.org/title/Udev#Allowing_regular_users_to_use_devices (see note)

Create this file to override existing udev rule(*):

sudoedit /etc/udev/rules.d/69-i2c-permissions.rules

with this content:

SUBSYSTEM=="i2c-dev", KERNEL=="i2c-[0-9]*", MODE="0660", GROUP="i2c", TAG+="uaccess"


(*) /usr/lib/udev/rules.d/60-i2c-tools.rules provided by i2c-tools package