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Hi Peter:

> -----Original Message-----
> From: Peter Zijlstra <[email protected]>
> Sent: Friday, September 8, 2023 9:24 PM
> To: Meng, Li (Jassmine) <[email protected]>
> Cc: Rafael J . Wysocki <[email protected]>; Huang, Ray
> <[email protected]>; [email protected]; linux-
> [email protected]; [email protected]; [email protected]; Shuah
> Khan <[email protected]>; [email protected];
> Fontenot, Nathan <[email protected]>; Sharma, Deepak
> <[email protected]>; Deucher, Alexander
> <[email protected]>; Limonciello, Mario
> <[email protected]>; Huang, Shimmer
> <[email protected]>; Yuan, Perry <[email protected]>; Du,
> Xiaojian <[email protected]>; Viresh Kumar <[email protected]>;
> Borislav Petkov <[email protected]>
> Subject: Re: [PATCH V5 4/7] cpufreq: Add a notification message that the
> highest perf has changed
>
> Caution: This message originated from an External Source. Use proper
> caution when opening attachments, clicking links, or responding.
>
>
> On Tue, Sep 05, 2023 at 09:51:13AM +0800, Meng Li wrote:
> > ACPI 6.5 section 8.4.6.1.1.1 specifies that Notify event 0x85 can be
> > emmitted to cause the the OSPM to re-evaluate the highest performance
> > register. Add support for this event.
> >
> > Signed-off-by: Meng Li <[email protected]>
> > Link:
> > https://uefi.org/specs/ACPI/6.5/08_Processor_Configuration_and_Control
> > .html?highlight=cppc#cpc-continuous-performance-control
> > ---
> >  drivers/acpi/processor_driver.c |  6 ++++++
> >  drivers/cpufreq/cpufreq.c       | 13 +++++++++++++
> >  include/linux/cpufreq.h         |  5 +++++
> >  3 files changed, 24 insertions(+)
> >
> > diff --git a/drivers/acpi/processor_driver.c
> > b/drivers/acpi/processor_driver.c index 4bd16b3f0781..29b2fb68a35d
> > 100644
> > --- a/drivers/acpi/processor_driver.c
> > +++ b/drivers/acpi/processor_driver.c
> > @@ -27,6 +27,7 @@
> >  #define ACPI_PROCESSOR_NOTIFY_PERFORMANCE 0x80  #define
> > ACPI_PROCESSOR_NOTIFY_POWER  0x81
> >  #define ACPI_PROCESSOR_NOTIFY_THROTTLING     0x82
> > +#define ACPI_PROCESSOR_NOTIFY_HIGEST_PERF_CHANGED    0x85
> >
> >  MODULE_AUTHOR("Paul Diefenbaugh");
> >  MODULE_DESCRIPTION("ACPI Processor Driver"); @@ -83,6 +84,11 @@
> > static void acpi_processor_notify(acpi_handle handle, u32 event, void
> *data)
> >               acpi_bus_generate_netlink_event(device->pnp.device_class,
> >                                                 dev_name(&device->dev), 
> > event, 0);
> >               break;
> > +     case ACPI_PROCESSOR_NOTIFY_HIGEST_PERF_CHANGED:
> > +             cpufreq_update_highest_perf(pr->id);
> > +             acpi_bus_generate_netlink_event(device->pnp.device_class,
> > +                                               dev_name(&device->dev), 
> > event, 0);
> > +             break;
> >       default:
> >               acpi_handle_debug(handle, "Unsupported event [0x%x]\n", 
> > event);
> >               break;
>
> I've obviously not read the link, but the above seems to suggest that every
> CPU that has its limits changed gets the 'interrupt' ?
[Meng, Li (Jassmine)]
Yes.
I will modify the link to 
https://uefi.org/specs/ACPI/6.5/05_ACPI_Software_Programming_Model.html#processor-device-notification-values

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