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Message-ID: <885c4c97e32148d4acdbb5fa2f4401f41ae76084.camel@puri.sm>
Date: Thu, 21 Jul 2022 19:14:46 +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 v5 2/3] power: domain: handle genpd correctly when
needing interrupts
Am Donnerstag, dem 21.07.2022 um 13:16 +0200 schrieb Ulf Hansson:
> On Thu, 21 Jul 2022 at 06:37, 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, 18 insertions(+)
> >
> > diff --git a/drivers/base/power/domain.c
> > b/drivers/base/power/domain.c
> > index 5a2e0232862e..ef77700e0def 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)
> > @@ -2079,6 +2080,13 @@ int pm_genpd_init(struct generic_pm_domain
> > *genpd,
> > genpd->dev_ops.start = pm_clk_resume;
> > }
> >
> > + if (genpd_irq_on(genpd)) {
> > + genpd->domain.ops.suspend = genpd_suspend_noirq;
> > + genpd->domain.ops.resume = genpd_resume_noirq;
> > + genpd->domain.ops.suspend_noirq = NULL;
> > + genpd->domain.ops.resume_noirq = NULL;
>
> Please move this a few lines above, just before we assign the _*noirq
> callbacks. In this way you don't need to reset thosepointers.
good point, thanks.
>
> > + }
> > +
> > /* The always-on governor works better with the
> > corresponding flag. */
> > if (gov == &pm_domain_always_on_gov)
> > genpd->flags |= GENPD_FLAG_RPM_ALWAYS_ON;
> > @@ -2769,6 +2777,11 @@ static int __genpd_dev_pm_attach(struct
> > device *dev, struct device *base_dev,
> > goto err;
> > dev_gpd_data(dev)->default_pstate = pstate;
> > }
> > +
> > + if (pd->domain.ops.suspend_noirq && (pd->flags &
> > GENPD_FLAG_IRQ_ON))
> > + dev_err(dev, "PM domain %s needs irqs but uses
> > noirq suspend\n",
> > + pd->name);
> > +
>
> This doesn't make sense, as it can never happen according to what we
> do in pm_genpd_init().
>
> What Lucas suggested in the other thread was to log a warning if a
> device's (that gets attached to genpd) bus/driver has _*noirq
> callbacks. That would make sense.
>
> Thinking more about this, perhaps we should move to use the
> _*late/early callbacks instead for genpd. This would decrease the
> window of potential problematic consumers users (drivers/buses).
>
ok, I'll probably send another version without this. I'm leaving for
vacations for a few weeks soon, so I'd rather do the essentials only
here and take notes about what could be added later, if that's ok.
thank you very much!
martin
> > return 1;
> >
> > err:
> > diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
> > index 76bc9e3ef5ff..03bb86e43550 100644
> > --- a/include/linux/pm_domain.h
> > +++ b/include/linux/pm_domain.h
> > @@ -61,6 +61,10 @@
> > * GENPD_FLAG_MIN_RESIDENCY: Enable the genpd governor to
> > consider its
> > * components' next wakeup when
> > determining the
> > * optimal idle state.
> > + *
> > + * GENPD_FLAG_IRQ_ON: genpd needs irqs to be able to
> > manage power
> > + * on/off. Use the outer
> > suspend/resume callbacks
> > + * instead of noirq for example.
> > */
> > #define GENPD_FLAG_PM_CLK BIT(0)
> > #define GENPD_FLAG_IRQ_SAFE BIT(1)
> > @@ -69,6 +73,7 @@
> > #define GENPD_FLAG_CPU_DOMAIN BIT(4)
> > #define GENPD_FLAG_RPM_ALWAYS_ON BIT(5)
> > #define GENPD_FLAG_MIN_RESIDENCY BIT(6)
> > +#define GENPD_FLAG_IRQ_ON BIT(7)
> >
> > enum gpd_status {
> > GENPD_STATE_ON = 0, /* PM domain is on */
> > --
> > 2.30.2
> >
>
> Kind regards
> Uffe
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