Re: [PATCH v3 1/4] ACPI: s2idle: Add a new ->check() callback for platform_s2idle_ops

["Limonciello, Mario" <mario.limonciello@xxxxxxx>]

On 8/30/2022 06:39, Rafael J. Wysocki wrote:
> On Mon, Aug 29, 2022 at 6:29 PM Mario Limonciello
> <mario.limonciello@xxxxxxx> wrote:
> > On some platforms it is found that Linux more aggressively enters s2idle
> > than Windows enters Modern Standby and this uncovers some synchronization
> > issues for the platform.  To aid in debugging this class of problems in
> > the future, add support for an extra optional callback intended for
> > drivers to emit extra debugging.
> >
> > Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
>
> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
>
> and I'm assuming that this is for Hans.

Thanks, and yeah I think it makes more sense for this to go through 
platform-x86.

> > ---
> > v2->v3:
> >   * Rename to *check
> > v1->v2:
> >   * Add a prototype for `acpi_s2idle_enter`
> >
> >   drivers/acpi/sleep.h      |  1 +
> >   drivers/acpi/x86/s2idle.c | 14 ++++++++++++++
> >   include/linux/acpi.h      |  1 +
> >   include/linux/suspend.h   |  1 +
> >   kernel/power/suspend.c    |  3 +++
> >   5 files changed, 20 insertions(+)
> >
> > diff --git a/drivers/acpi/sleep.h b/drivers/acpi/sleep.h
> > index 7fe41ee489d6..d960a238be4e 100644
> > --- a/drivers/acpi/sleep.h
> > +++ b/drivers/acpi/sleep.h
> > @@ -18,6 +18,7 @@ static inline acpi_status acpi_set_waking_vector(u32 wakeup_address)
> >   extern int acpi_s2idle_begin(void);
> >   extern int acpi_s2idle_prepare(void);
> >   extern int acpi_s2idle_prepare_late(void);
> > +extern void acpi_s2idle_check(void);
> >   extern bool acpi_s2idle_wake(void);
> >   extern void acpi_s2idle_restore_early(void);
> >   extern void acpi_s2idle_restore(void);
> > diff --git a/drivers/acpi/x86/s2idle.c b/drivers/acpi/x86/s2idle.c
> > index f9ac12b778e6..474aa46f82f6 100644
> > --- a/drivers/acpi/x86/s2idle.c
> > +++ b/drivers/acpi/x86/s2idle.c
> > @@ -486,6 +486,19 @@ int acpi_s2idle_prepare_late(void)
> >          return 0;
> >   }
> >
> > +void acpi_s2idle_check(void)
> > +{
> > +       struct acpi_s2idle_dev_ops *handler;
> > +
> > +       if (!lps0_device_handle || sleep_no_lps0)
> > +               return;
> > +
> > +       list_for_each_entry(handler, &lps0_s2idle_devops_head, list_node) {
> > +               if (handler->check)
> > +                       handler->check();
> > +       }
> > +}
> > +
> >   void acpi_s2idle_restore_early(void)
> >   {
> >          struct acpi_s2idle_dev_ops *handler;
> > @@ -527,6 +540,7 @@ static const struct platform_s2idle_ops acpi_s2idle_ops_lps0 = {
> >          .begin = acpi_s2idle_begin,
> >          .prepare = acpi_s2idle_prepare,
> >          .prepare_late = acpi_s2idle_prepare_late,
> > +       .check = acpi_s2idle_check,
> >          .wake = acpi_s2idle_wake,
> >          .restore_early = acpi_s2idle_restore_early,
> >          .restore = acpi_s2idle_restore,
> > diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> > index 6f64b2f3dc54..acaa2ddc067d 100644
> > --- a/include/linux/acpi.h
> > +++ b/include/linux/acpi.h
> > @@ -1075,6 +1075,7 @@ acpi_status acpi_os_prepare_extended_sleep(u8 sleep_state,
> >   struct acpi_s2idle_dev_ops {
> >          struct list_head list_node;
> >          void (*prepare)(void);
> > +       void (*check)(void);
> >          void (*restore)(void);
> >   };
> >   int acpi_register_lps0_dev(struct acpi_s2idle_dev_ops *arg);
> > diff --git a/include/linux/suspend.h b/include/linux/suspend.h
> > index 70f2921e2e70..03ed42ed2c7f 100644
> > --- a/include/linux/suspend.h
> > +++ b/include/linux/suspend.h
> > @@ -191,6 +191,7 @@ struct platform_s2idle_ops {
> >          int (*begin)(void);
> >          int (*prepare)(void);
> >          int (*prepare_late)(void);
> > +       void (*check)(void);
> >          bool (*wake)(void);
> >          void (*restore_early)(void);
> >          void (*restore)(void);
> > diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
> > index 827075944d28..c6272d466e58 100644
> > --- a/kernel/power/suspend.c
> > +++ b/kernel/power/suspend.c
> > @@ -136,6 +136,9 @@ static void s2idle_loop(void)
> >                          break;
> >                  }
> >
> > +               if (s2idle_ops && s2idle_ops->check)
> > +                       s2idle_ops->check();
> > +
> >                  s2idle_enter();
> >          }
> >
> > --
> > 2.34.1