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SubjectRe: [PATCH] watchdog: pnx4008: readout watchddog state
On Thu, Apr 11, 2019 at 06:13:39PM +0200, Alexandre Belloni wrote:
> On 11/04/2019 09:03:05-0700, Guenter Roeck wrote:
> > Hi Alexandre,
> >
> > On Thu, Apr 11, 2019 at 05:36:46PM +0200, Alexandre Belloni wrote:
> > > Readout the enabled state so it is possible to get the pre-userspace
> > > handler working. Also, avoid disabling the watchdog when nowayout is set to
> > > ensure the watchdog continues working and triggers if there is an issue
> > > later in the boot or if userspace fails to start.
> > >
> > > Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
> > > ---
> > > drivers/watchdog/pnx4008_wdt.c | 6 +++++-
> > > 1 file changed, 5 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/watchdog/pnx4008_wdt.c b/drivers/watchdog/pnx4008_wdt.c
> > > index 8e261799c84e..9e3714e3814c 100644
> > > --- a/drivers/watchdog/pnx4008_wdt.c
> > > +++ b/drivers/watchdog/pnx4008_wdt.c
> > > @@ -209,7 +209,11 @@ static int pnx4008_wdt_probe(struct platform_device *pdev)
> > > watchdog_set_nowayout(&pnx4008_wdd, nowayout);
> > > watchdog_set_restart_priority(&pnx4008_wdd, 128);
> > >
> > > - pnx4008_wdt_stop(&pnx4008_wdd); /* disable for now */
> > > + if (readl(WDTIM_CTRL(wdt_base)) & COUNT_ENAB)
> > > + set_bit(WDOG_HW_RUNNING, &pnx4008_wdd.status);
> > > +
> > > + if (!nowayout)
> > > + pnx4008_wdt_stop(&pnx4008_wdd); /* disable for now */
> >
> > I don't see the point of stopping the watchdog here, even though that is the
> > old behavior. If it is possible to detect that the watchdog is running, we
> > can let the core handle pings until the watchdog device is opened. The code
> > above does that, but only if nowayout is set. That seems inconsistent and
> > unnecessary. Is there a downside to doing that unconditionally ?
> >
>
> I guess the downside is the change of behaviour. I don't think many will
> be affected but they will have to ensure the core pings the watchdog
> until the device is open. WATCHDOG_HANDLE_BOOT_ENABLED is y by default
> so that should be fine for most.
>
Your code already does change behavior if nowayout is set.

> Honestly, I would just never disable the watchdog, that is the whole
> point of this patch. If you are fine with that, I will just remove the
> line.
>
Please.

Thanks,
Guenter

>
> > Nitpick: s/watchddog/watchdog/ in subject line.
> >
>
> I'll fix it.
>
>
> --
> Alexandre Belloni, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com

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