How is the RPi HW watchdog implemented and is it configurable


I have a couple of questions regarding the HW watchdog of the Raspberry Pi 4 and its implementation in balenaOS:

  • it says in this forum post that balenaOS utilizes the watchdog already
    • So am I correct that it is enabled by default and I don’t need to configure it myself for my devices?
  • the watchdog manual specifies that the watchdog can use several tests to check the system status, including free memory, file accessibility, too high workload, network traffic, etc.
    • Am I looking at the correct reference to see what the watchdog (that balenaOS uses) is able to do?
    • What checks are active in the balenaOS implementation of the watchdog?
    • Can I configure the watchdog in balenaOS to make it more specific to my usecase?

Hi, indeed, balenaOS uses the hardware watchdog and it is enabled by default. Application should not worry about it. The hostOS configures systemd with a 10 secs timeout.
BalenaOS does not use the watchdog daemon you refer to, and it cannot be configured in any other way. It is meant to reboot the device if systemd does not refresh it on time.