[Skiboot] [PATCH 3/3] ipmi/wdt: Add ipmi watchdog timer support
benh at au1.ibm.com
Thu Jan 29 04:28:40 AEDT 2015
On Wed, 2015-01-28 at 16:37 +1100, Stewart Smith wrote:
> Alistair Popple <alistair at popple.id.au> writes:
> > Add support for an ipmi watchdog timer. This patch will cause the
> > system to be reset if opal_run_pollers() isn't called for more than
> > about 60 seconds.
> > The timer is reset just prior to running the payload. It is the
> > responsibility of the payload to ensure either opal_run_pollers() is
> > called frequently enough or to disable the watchdog timer by sending
> > appropriate ipmi commands.
> I'm a little uncomfortable in changing what is essentially an ABI here
> without having the payload explicitly enable the WDT.
> I worry about:
> - existing payloads
> - will current payloads behave correctly? Do we have anything that
> will currently make sure opal_run_pollers() is called frequently?
Not necessarily. I think we put a kthread in recent kernels to do it but
otherwise, we are utterly dependent on having hvc console call at a
reasonably regular interval.
> - different ABI for payload kernel versus host kernel. If payload
> (i.e. petitboot environment) disables the watchdog timer, then we'll
> have different behavior if booted as payload versus as petitboot.
> - some concern about really low power modes and having to muck with
> I think I'd prefer us to have to enable the watchdog explicitly...
> Ben, your thoughts?
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