RE: [PATCH] acpi/sleep: Use the FADT to prefer Suspend-to-Idle instead of S3

[<Mario.Limonciello@xxxxxxxx>]

> -----Original Message-----
> From: rjwysocki@xxxxxxxxx [mailto:rjwysocki@xxxxxxxxx] On Behalf Of
> Rafael J. Wysocki
> Sent: Thursday, November 10, 2016 5:54 PM
> To: Limonciello, Mario <Mario_Limonciello@xxxxxxxx>
> Cc: ACPI Devel Maling List <linux-acpi@xxxxxxxxxxxxxxx>; Len Brown
> <lenb@xxxxxxxxxx>; Rafael J . Wysocki <rjw@xxxxxxxxxxxxx>; Andy
> Lutomirski <luto@xxxxxxxxxx>
> Subject: Re: [PATCH] acpi/sleep: Use the FADT to prefer Suspend-to-Idle
> instead of S3
> 
> On Thu, Nov 10, 2016 at 10:35 PM, Mario Limonciello
> <mario.limonciello@xxxxxxxx> wrote:
> > If the ACPI_FADT_LOW_POWER_S0 bit is set, this indicates the platform
> > should get identical or better performance using Suspend-To-Idle.
> >
> > By removing S3 and S1 userspace will prefer suspend-to-idle in
> > these situations too.
> >
> > Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxxx>
> > ---
> >  drivers/acpi/sleep.c | 11 +++++++++++
> >  1 file changed, 11 insertions(+)
> >
> > diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
> > index deb0ff7..ff1d8f1 100644
> > --- a/drivers/acpi/sleep.c
> > +++ b/drivers/acpi/sleep.c
> > @@ -171,6 +171,12 @@ static int __init init_nvs_nosave(const struct
> dmi_system_id *d)
> >         return 0;
> >  }
> >
> > +static bool suspend_to_idle_preferred(void)
> > +{
> > +       return (acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0);
> > +}
> > +
> > +
> >  static struct dmi_system_id acpisleep_dmi_table[] __initdata = {
> >         {
> >         .callback = init_old_suspend_ordering,
> > @@ -908,6 +914,11 @@ int __init acpi_sleep_init(void)
> >                 acpi_no_s5 = true;
> >         }
> >
> > +       if (suspend_to_idle_preferred()) {
> > +               sleep_states[ACPI_STATE_S3] = 0;
> > +               sleep_states[ACPI_STATE_S1] = 0;
> > +       }
> > +
> >         supported[0] = 0;
> >         for (i = 0; i < ACPI_S_STATE_COUNT; i++) {
> >                 if (sleep_states[i])
> > --
> 
> I'd do that in a different way.
> 
> Let me cut a patch for that (I haven't had the time to do that yet)
> and we'll see.
> 
> Thanks,
> Rafael

OK, look forward to seeing the approach you want to go with this
instead.

Thanks,
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