linux-kernel - Re: [PATCH v6 1/2] power: domain: handle genpd correctly when needing interrupts

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Date:   Thu, 28 Jul 2022 11:19:56 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     Martin Kepplinger <martin.kepplinger@...i.sm>,
        Kevin Hilman <khilman@...nel.org>,
        Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        Pavel Machek <pavel@....cz>, kernel@...i.sm,
        dl-linux-imx <linux-imx@....com>,
        Mark Brown <broonie@...nel.org>,
        Lucas Stach <l.stach@...gutronix.de>, aford173@...il.com,
        Linux PM <linux-pm@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v6 1/2] power: domain: handle genpd correctly when needing interrupts

On Tue, 26 Jul 2022 at 20:33, Rafael J. Wysocki <rafael@...nel.org> wrote:
>
> On Tue, Jul 26, 2022 at 5:07 PM Ulf Hansson <ulf.hansson@...aro.org> wrote:
> >
> > On Tue, 26 Jul 2022 at 10:33, Martin Kepplinger
> > <martin.kepplinger@...i.sm> wrote:
> > >
> > > If for example the power-domains' power-supply node (regulator) needs
> > > interrupts to work, the current setup with noirq callbacks cannot
> > > work; for example a pmic regulator on i2c, when suspending, usually already
> > > times out during suspend_noirq:
> > >
> > > [   41.024193] buck4: failed to disable: -ETIMEDOUT
> > >
> > > So fix system suspend and resume for these power-domains by using the
> > > "outer" suspend/resume callbacks instead. Tested on the imx8mq-librem5 board,
> > > but by looking at the dts, this will fix imx8mq-evk and possibly many other
> > > boards too.
> > >
> > > This is designed so that genpd providers just say "this genpd needs
> > > interrupts" (by setting the flag) - without implying an implementation.
> > >
> > > Initially system suspend problems had been discussed at
> > > https://lore.kernel.org/linux-arm-kernel/20211002005954.1367653-8-l.stach@pengutronix.de/
> > > which led to discussing the pmic that contains the regulators which
> > > serve as power-domain power-supplies:
> > > https://lore.kernel.org/linux-pm/573166b75e524517782471c2b7f96e03fd93d175.camel@puri.sm/T/
> > >
> > > Signed-off-by: Martin Kepplinger <martin.kepplinger@...i.sm>
> > > ---
> > >  drivers/base/power/domain.c | 13 +++++++++++--
> > >  include/linux/pm_domain.h   |  5 +++++
> > >  2 files changed, 16 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
> > > index 5a2e0232862e..58376752a4de 100644
> > > --- a/drivers/base/power/domain.c
> > > +++ b/drivers/base/power/domain.c
> > > @@ -130,6 +130,7 @@ static const struct genpd_lock_ops genpd_spin_ops = {
> > >  #define genpd_is_active_wakeup(genpd)  (genpd->flags & GENPD_FLAG_ACTIVE_WAKEUP)
> > >  #define genpd_is_cpu_domain(genpd)     (genpd->flags & GENPD_FLAG_CPU_DOMAIN)
> > >  #define genpd_is_rpm_always_on(genpd)  (genpd->flags & GENPD_FLAG_RPM_ALWAYS_ON)
> > > +#define genpd_irq_on(genpd)            (genpd->flags & GENPD_FLAG_IRQ_ON)
> > >
> > >  static inline bool irq_safe_dev_in_sleep_domain(struct device *dev,
> > >                 const struct generic_pm_domain *genpd)
> > > @@ -2065,8 +2066,15 @@ int pm_genpd_init(struct generic_pm_domain *genpd,
> > >         genpd->domain.ops.runtime_suspend = genpd_runtime_suspend;
> > >         genpd->domain.ops.runtime_resume = genpd_runtime_resume;
> > >         genpd->domain.ops.prepare = genpd_prepare;
> > > -       genpd->domain.ops.suspend_noirq = genpd_suspend_noirq;
> > > -       genpd->domain.ops.resume_noirq = genpd_resume_noirq;
> > > +
> > > +       if (genpd_irq_on(genpd)) {
> > > +               genpd->domain.ops.suspend = genpd_suspend_noirq;
> > > +               genpd->domain.ops.resume = genpd_resume_noirq;
> > > +       } else {
> > > +               genpd->domain.ops.suspend_noirq = genpd_suspend_noirq;
> > > +               genpd->domain.ops.resume_noirq = genpd_resume_noirq;
> >
> > As we discussed previously, I am thinking that it may be better to
> > move to using genpd->domain.ops.suspend_late and
> > genpd->domain.ops.resume_early instead.
>
> Should I take this as a change request?

Yes.

>
> > Beside this, I think the $subject patch looks good to me.
>
> Or not?

The patch needs to be updated before I give it my blessing, but the
only changes that are needed are the minor things I pointed out above.
Sorry if it was not clear enough.

Kind regards
Uffe