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

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Date:   Fri, 19 Aug 2022 11:17:40 +0200
From:   Martin Kepplinger <martin.kepplinger@...i.sm>
To:     Ulf Hansson <ulf.hansson@...aro.org>
Cc:     rafael@...nel.org, khilman@...nel.org, robh@...nel.org,
        krzysztof.kozlowski@...aro.org, shawnguo@...nel.org,
        s.hauer@...gutronix.de, festevam@...il.com, pavel@....cz,
        kernel@...i.sm, linux-imx@....com, broonie@...nel.org,
        l.stach@...gutronix.de, aford173@...il.com,
        linux-pm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v6 1/2] power: domain: handle genpd correctly when
 needing interrupts

Am Dienstag, dem 26.07.2022 um 17:07 +0200 schrieb Ulf Hansson:
> 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.

Wouldn't that better be a separate patch (on top)? Do you really want
me to change the current behaviour (default case) to from noirq to
late? Then I'll resend this series with such a patch added.

thanks,

                              martin

> 
> Beside this, I think the $subject patch looks good to me.
> 
> [...]
> 
> Kind regards
> Uffe