I've been fooling around with our server in the garage a bit more lately than I have in the past. One thing I did was just go through /etc/defaults/rc.conf to see what was new since last time I looked.... and I discovered watchdogd_enable.
"Hmm, what's this?"
Well, long and short, I discovered that it links up with the ichwd device to provide a hardware watchdog. If watchdogd doesn't "report in" every so often to the ichwd device, the machine will get a hard reset. I tested this by giving watchdogd a kill -9 and waiting (it has to be a -9 because -1 and -15 give watchdogd a chance to disable the hardware watchdog under the presumption that you are stopping it because you don't want it to run, not because you want it to cold-cock the machine). Sure enough, a few seconds later the machine reboot.
So
If attempting to load ichwd doesn't work, it may be because you lack the corresponding hardware or because that hardware may be disabled in the BIOS or some such. The driver attempts to discover this when loaded.
So far as I can tell, from /sys/amd64/conf/NOTES, the ichwd is the only hardware watchdog available.
"Hmm, what's this?"
Well, long and short, I discovered that it links up with the ichwd device to provide a hardware watchdog. If watchdogd doesn't "report in" every so often to the ichwd device, the machine will get a hard reset. I tested this by giving watchdogd a kill -9 and waiting (it has to be a -9 because -1 and -15 give watchdogd a chance to disable the hardware watchdog under the presumption that you are stopping it because you don't want it to run, not because you want it to cold-cock the machine). Sure enough, a few seconds later the machine reboot.
So
Code:
echo 'ichwd_load="YES"' >> /boot/loader.conf
kldload ichwd
echo 'watchdogd_enable="YES"' >> /etc/rc.conf
/etc/rc.d/watchdogd start
If attempting to load ichwd doesn't work, it may be because you lack the corresponding hardware or because that hardware may be disabled in the BIOS or some such. The driver attempts to discover this when loaded.
So far as I can tell, from /sys/amd64/conf/NOTES, the ichwd is the only hardware watchdog available.