systemd watchdog with wdat_wdt

[Jared Norris]

On Fri, 12 Sept 2025 at 21:43, Tdev Test <tpdev.tester at gmail.com> wrote:

> Hi,
>
> I'm not sure if my first message reached the list, so please excuse any
> duplicate emails.
>
> I would like to use the `systemd` watchdog as described in [1] on a
> Odroid-H4-Ultra. A BIOS update enabled the corresponding setting and the
> hardware is available[2].
>
> I installed the `watchdog` package which brings the `wdat_wdt` kernel
> module, but I'm not using the watchdog program itself. I can load the
> module manually via `modprobe  wdat_wdt` (=> `/dev/watchdog` is available)
> and `wdctl` shows, that everything is working fine.
>
> Unfortunately, I cannot load the kernel module automatically at boot time,
> adding a file `/etc/modules-load.d/wdat_wdt.conf` => reboot => module not
> loaded.
>
> journalctl -u systemd-modules-load.service: "... Module 'wdat_wdt' is
> deny-listed (by kmod) ..."
>
> It turned out, that  wdat_wdt is blacklisted in
> /lib/modprobe.d/blacklist_linux_6.8.0-79-generic.conf. This seems to be a
> auto generated file (corresponding to the current kernel version). I guess
> editing this file manually is not a good idea.
>
> Why is wdat_wdt blacklisted?
>
> Is there any replacement for wdat_wdt?
>
> How to make use of the watchdog hardware with systemd?
>
> Kind regards
>
> Thomas
>
> [1] https://0pointer.de/blog/projects/watchdog.html
>
> [2] https://wiki.odroid.com/odroid-h4/application_note/tco_watchdog_timer
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Hi Thomas,

Confirming this message and the previous one have been received on the
list. It appears there isn't anyone who has come across the issue you're
describing sorry and may not know how to assist.

I can't offer much other than to confirm you'd seed the various postings on
google about it? Some look promising:

   - https://www.reddit.com/r/archlinux/comments/1124b9a/comment/j8md8gn/
   -
   https://forum.manjaro.org/t/watchdog-did-not-stop-how-to-revert-blacklist-conf/130573


Regards,

Jared
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