Re: [PATCHv1] ACPI: processor idle: Allow playing dead in C3 state

[Gong, Richard]

Hi Rafael,

On 9/24/2021 11:31 AM, Rafael J. Wysocki wrote:
> On Wed, Sep 22, 2021 at 3:31 PM Richard Gong <richard.gong@xxxxxxx> wrote:
> > When some cores are disabled on AMD platforms, the system will no longer
> > be able to enter suspend-to-idle s0ix.
> >
> > Update to allow playing dead in C3 state so that the CPUs can enter the
> > deepest state on AMD platforms.
> >
> > BugLink: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgitlab.freedesktop.org%2Fdrm%2Famd%2F-%2Fissues%2F1708&amp;data=04%7C01%7Crichard.gong%40amd.com%7Ca5c0db9ce02b4cd0864f08d97f78d33f%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637680980065602427%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=dIO5PDjpncLFIt0aGaTrKJHYIkJm8A4YByGn1%2FsHrtM%3D&amp;reserved=0
> > Suggested-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> > Signed-off-by: Richard Gong <richard.gong@xxxxxxx>
> > ---
> >   drivers/acpi/processor_idle.c | 3 ++-
> >   1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
> > index f37fba9e5ba0..61d5a72d218e 100644
> > --- a/drivers/acpi/processor_idle.c
> > +++ b/drivers/acpi/processor_idle.c
> > @@ -789,7 +789,8 @@ static int acpi_processor_setup_cstates(struct acpi_processor *pr)
> >                  state->enter = acpi_idle_enter;
> >
> >                  state->flags = 0;
> > -               if (cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2) {
> > +               if (cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2
> > +                       || cx->type == ACPI_STATE_C3) {
> >                          state->enter_dead = acpi_idle_play_dead;
> >                          drv->safe_state_index = count;
> >                  }
> > --
> Tentatively applied as 5.16 material, but have you done any research
> on why this restriction has been there in the first place?

Yes, we need this change to align with the updated firmware on AMD 
platforms.

Regards,

Richard