Re: [PATCH 2/2] remoteproc: core: Prevent sleep when rproc crashes

[rishabhb]

On 2020-04-07 15:29, Bjorn Andersson wrote:
> On Wed 19 Feb 18:11 PST 2020, Siddharth Gupta wrote:
>
> > Remoteproc recovery should be fast and any delay will have an impact 
> > on the
> > user-experience. Use power management APIs (pm_stay_awake and 
> > pm_relax) to
> > ensure that the system does not go to sleep.
> >
> > Signed-off-by: Siddharth Gupta <sidgup@xxxxxxxxxxxxxx>
> > ---
> >  drivers/remoteproc/remoteproc_core.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/drivers/remoteproc/remoteproc_core.c 
> > b/drivers/remoteproc/remoteproc_core.c
> > index 5ab65a4..52e318c 100644
> > --- a/drivers/remoteproc/remoteproc_core.c
> > +++ b/drivers/remoteproc/remoteproc_core.c
> > @@ -1712,6 +1712,8 @@ static void rproc_crash_handler_work(struct 
> > work_struct *work)
> >
> >  	if (!rproc->recovery_disabled)
> >  		rproc_trigger_recovery(rproc);
> > +
> > +	pm_relax(&rproc->dev);
> >  }
> >
> >  /**
> > @@ -2242,6 +2244,8 @@ void rproc_report_crash(struct rproc *rproc, 
> > enum rproc_crash_type type)
> >  		return;
> >  	}
> >
> > +	pm_stay_awake(&rproc->dev);
>
> Following Mathieu's question I was expecting you to do this on
> rproc->dev.parent.
>
> But looking at the implementation of pm_stay_awake(), it ends up being 
> a
> nop if dev->power.wakeup isn't specified. This in turn seems to come
> from device_wakeup_enable(), which will bail if dev->power.can_wakeup 
> is
> not set. But I don't see where this would be set for either the 
> platform
> driver or the remoteproc's struct device - and neither one of them have
> a "wakeup" attribute in sysfs.
>
> Is there some additional plumbing needed for this?
We should be able to create a standalone wakeup source using 
wakeup_source_init.
Then we can use _pm_stay_awake and _pm_relax on it.
> Regards,
> Bjorn
>
> > +
> >  	dev_err(&rproc->dev, "crash detected in %s: type %s\n",
> >  		rproc->name, rproc_crash_to_string(type));
> >
> > --
> > Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> > a Linux Foundation Collaborative Project