watchdog service is not working because /dev/watchdog does not exist

Question

There is a ITE8783 watchdog chip placed within my machine (OS Ubuntu 14.04.1). The kernel module it87 supports is. This module was not automatically loaded on startup. So I added it87 to /etc/modules. Now the module loads at startup.

it87: Found IT8783F chip at 0x290, revision 0
it87: Beeping is supported
it87 it87.656: Detected broken BIOS defaults, disabling PWM interface

I have recognized that there is no /dev/watchdog device showing up. So I googled around and create it doing mknod /dev/watchdog c 10 130.

Now the device appears but I think the watchdog process doesn't take magically care? Furthermore, is there anything missing because /dev/watchdog is not created automatically? Should I create the device with udev or anything else? I'm not that familiar with kernel modules, devices and watchdogs. So please give me a hint. Thanks!

Solution

Info can be found here: http://www.sat.dundee.ac.uk/psc/watchdog/watchdog-configure.html

If all else fails, and you have no hardware support, you can load the 'softdog' module to emulate some of the capabilities in software. However, this will provide greatly reduced protection as there is nothing to recover from a kernel panic, or a bad peripheral driver that blocks a software reboot.

Based on this we can conclude that your board does not have HW watchdog peripheral (or kernel does not insert appropriate module for it).

You can then fallback to softdog:

root@Hegel:/dev# ls /dev/watchdog
ls: cannot access /dev/watchdog: No such file or directory
root@Hegel:/dev# modprobe softdog
root@Hegel:/dev# ls /dev/watchdog
/dev/watchdog

Comments

[wenzul]

Thanks for your answer. My board has the chip IT8783F. And if I wrote if I load it87 manually, the log gives me a feedback that it was detected. But no device was created automatically. I will post the output of lm-sensors tomorrow.