systemd watchdog with wdat_wdt

[Little Girl]

Hey there,

Jared Norris wrote:
>Tdev Test wrote:

>> Why is wdat_wdt blacklisted?
>>
>> Is there any replacement for wdat_wdt?
>>
>> How to make use of the watchdog hardware with systemd?

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

Same here, so with my nonexistent knowledge of this topic, I thought
I'd jump in with some promising-looking Google AI output. I've
included the link I used and its output, since the output bafflingly
changes each time the URL is visited and some of the reloads don't
contain all of this information:

From:

https://www.google.com/search?client=ubuntu-sn&channel=fs&q=ubuntu+why+is+wdat+blacklisted+in+%2Flib%2Fmodprobe.d%2Fblacklist_linux_6.8.0-79-generic.conf

AI Overview
The wdat module (wdat_wdt) is blacklisted in /lib/modprobe.d/blacklist_linux_6.8.0-79-generic.conf to prevent conflicts with other system components, particularly when another watchdog timer is already configured. 
Here is a more detailed breakdown of the reasons:

    Preventing system conflicts: The wdat_wdt module is a driver for the ACPI (Advanced Configuration and Power Interface) Watchdog Action Table (WDAT). A watchdog timer is a hardware or software feature that can automatically reboot a system if it becomes unresponsive. In many modern systems, the watchdog timer is handled by other, more reliable mechanisms, such as those provided by the system's firmware. Loading the ACPI wdat module could cause a conflict if another watchdog driver is already in use, leading to system instability or unpredictable behavior.
    Avoiding multiple watchdog timers: Having more than one watchdog timer running at the same time is generally a bad idea. If both timers are configured to reboot the system, they could interfere with each other and prevent a graceful shutdown. Blacklisting wdat ensures that the system relies on a single, correctly configured watchdog mechanism.
    Autogenerated file: The blacklist file you reference, /lib/modprobe.d/blacklist_linux_6.8.0-79-generic.conf, is autogenerated for your specific kernel version. This means that the decision to blacklist this module was made during the kernel's packaging process to ensure stability across a wide range of hardware. 

What to do if you need the wdat module
In almost all cases, you should not edit this autogenerated file. If you have a specific reason to enable the wdat watchdog, you can follow these steps to override the blacklisting safely:

    Create a new modprobe file: Create a new file in the /etc/modprobe.d/ directory, for example, wdat.conf.
    Add an override rule: Add the following line to the new file to override the blacklist:
    install wdat_wdt /sbin/modprobe --ignore-install wdat_wdt $CMDLINE_OPTS
    Update initramfs: Run the command sudo update-initramfs -u to apply the changes.
    Reboot: Restart your system to load the module.
 
-- 
Little Girl

There is no spoon.