How to disable softdog and use hardware watchdog instead ?

shodan

Active Member
Sep 1, 2022
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Hi,
I have a flakey system on proxmox 9
It's a new-old system that should have worked but I didn't test earlier
Motherboard is a gigabyte B450M DS3H V2 with latest bios F67h 08/12/2025

So, to begin with I only have the softdog watchdog loaded
So I load the hardware watchdog sp5100_tco

Code:
root@proutmox:~# cat /sys/class/watchdog/watchdog0/identity
Software Watchdog
root@proutmox:~# cat /sys/class/watchdog/watchdog1/identity
cat: /sys/class/watchdog/watchdog1/identity: No such file or directory
root@proutmox:~# modprobe sp5100_tco
root@proutmox:~# cat /sys/class/watchdog/watchdog1/identity
SP5100 TCO timer

This appears to work.

Next I create these files, to blacklist softdog and load sp5100_tco

Code:
root@proutmox:~# cat /etc/modprobe.d/blacklist-softdog.conf
blacklist softdog
root@proutmox:~# cat /etc/modules-load.d/sp5100_tco.conf
sp5100_tco
root@proutmox:~#

Lastly I update initramfs and reboot

Code:
root@proutmox:~# update-initramfs -u -k all
update-initramfs: Generating /boot/initrd.img-6.14.8-2-pve
Running hook script 'zz-proxmox-boot'..
Re-executing '/etc/kernel/postinst.d/zz-proxmox-boot' in new private mount namespace..
No /etc/kernel/proxmox-boot-uuids found, skipping ESP sync.
root@proutmox:~# reboot
root@proutmox:~# modprobe -v sp5100_tco
insmod /lib/modules/6.14.8-2-pve/kernel/drivers/watchdog/sp5100_tco.ko
root@proutmox:~#


However after a reboot, still, softdog is loaded and sp5100_tco is not

Code:
root@proutmox:~# lsmod | grep softd
softdog                16384  2
root@proutmox:~# lsmod | grep sp5100
root@proutmox:~#

The blacklist file appears in lsinitramfs

Code:
root@proutmox:~# lsinitramfs /boot/initrd.img-$(uname -r) | grep softdog
etc/modprobe.d/blacklist-softdog.conf
usr/lib/modules/6.14.8-2-pve/kernel/drivers/watchdog/softdog.ko
root@proutmox:~#

What am I doing wrong ?

One suggestion I have is to override softdog module command with this ?

Code:
echo "install softdog /bin/true" > /etc/modprobe.d/disable-softdog.conf

Should I try that ?
 
Hello,

Better to use Proxmox defaults but if you really want to use watchdog and disable softdog you can do it by your own risk.
 
Hello!

Have you seen the documentation section about configuring a hardware watchdog? You probably still have the default value (softdog) set there, which is why it resets on reboot.

Is there a reason you want to switch to a hardware watchdog?
 
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