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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Tue, 26 Jul 2022 20:33:17 +0200
Message-ID: <CAJZ5v0hG4+z=ypDudiSnhG1SUxfLv+EFsUGOjQEqUi0EKH3+Rw@mail.gmail.com>
Subject: Re: [PATCH v6 1/2] power: domain: handle genpd correctly when needing interrupts
To:     Ulf Hansson <ulf.hansson@linaro.org>
Cc:     Martin Kepplinger <martin.kepplinger@puri.sm>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Kevin Hilman <khilman@kernel.org>,
        Rob Herring <robh@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        Pavel Machek <pavel@ucw.cz>, kernel@puri.sm,
        dl-linux-imx <linux-imx@nxp.com>,
        Mark Brown <broonie@kernel.org>,
        Lucas Stach <l.stach@pengutronix.de>, aford173@gmail.com,
        Linux PM <linux-pm@vger.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>
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On Tue, Jul 26, 2022 at 5:07 PM Ulf Hansson <ulf.hansson@linaro.org> wrote:
>
> On Tue, 26 Jul 2022 at 10:33, Martin Kepplinger
> <martin.kepplinger@puri.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@puri.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?

> Beside this, I think the $subject patch looks good to me.

Or not?