Re: [PATCH] xen/rpi4: implement watchdog-based reset

[Julien Grall <julien@xxxxxxx>]

Hi,

On 04/06/2020 01:15, Corey Minyard wrote:
> On Wed, Jun 03, 2020 at 03:31:56PM -0700, Stefano Stabellini wrote:
> > Touching the watchdog is required to be able to reboot the board.
> >
> > The implementation is based on
> > drivers/watchdog/bcm2835_wdt.c:__bcm2835_restart in Linux.
> Ah, I was looking at this just today, as it had been annoying me
> greatly.  This works for me, so:
>
> Tested-by: Corey Minyard <cminyard@xxxxxxxxxx>
>
> However, I was wondering if it might be better to handle this by failing
> the operation in xen and passing it back to dom0 to do.  On the Pi you
> send a firmware message to reboot, and that seems like too much to do in
> Xen, but it would seem possible to send this back to dom0. 
I don't think this is possible in the current setup. Xen will usually 
restart the platform if Dom0 requested a clean reboot or crashed. So the 
domain wouldn't be in state to service such call.
> Just a
> thought, as it might be a more general fix for other devices in the same
> situation.
What are the devices you have in mind?

Cheers,

--
Julien Grall