Re: watchdog start on restart

[Ivan Mikhaylov]

On Thu, 2020-09-03 at 13:13 +0200, Christophe Leroy wrote:

> You want to start the watchdog just before calling 'reboot' but want to 
> make sure that the watchdog will not reset the board before all 
> userspace has shut down correctly ?

Yes, just for an example, in the nature exists some aspeed2400/2500 board which
has 2 watchdog devices and 2 spi flash memories. By default it starts from 1 spi
flash. When watchdog triggers, on next boot, it's automatically starts from 2
flash, also you can manually switch from 1 spi flash to 2 with 2 watchdog device
by trigger of it, like transparent reload from 1 spi flash side to 2.

> But what is the purpose of the watchdog then, isn't it there to make 
> sure that the machine gets reboot within a given timeout anyway in case 
> some userspace takes too long to shut down ?

Usually, yes.

Thanks.