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SubjectRe: [PATCH v3 6/7] thermal/drivers/cpu_cooling: Introduce the cpu idle cooling driver
On Mon, Apr 16, 2018 at 02:49:35PM +0200, Daniel Lezcano wrote:
> On 16/04/2018 14:31, Sudeep Holla wrote:
> > On Mon, Apr 16, 2018 at 02:10:30PM +0200, Daniel Lezcano wrote:
> >> On 16/04/2018 12:10, Viresh Kumar wrote:
> >>> On 16-04-18, 12:03, Daniel Lezcano wrote:
> >>>> On 16/04/2018 11:50, Viresh Kumar wrote:
> >>>>> On 16-04-18, 11:45, Daniel Lezcano wrote:
> >>>>>> Can you elaborate a bit ? I'm not sure to get the point.
> >>>>>
> >>>>> Sure. With your current code on Hikey960 (big/LITTLE), you end up
> >>>>> creating two cooling devices, one for the big cluster and one for
> >>>>> small cluster. Which is the right thing to do, as we also have two
> >>>>> cpufreq cooling devices.
> >>>>>
> >>>>> But with the change Sudeep is referring to, the helper you used to get
> >>>>> cluster id will return 0 (SoC id) for all the 8 CPUs. So your code
> >>>>> will end up creating a single cpuidle cooling device for all the CPUs.
> >>>>> Which would be wrong.
> >>>>
> >>>> Is the semantic of topology_physical_package_id changing ?
> >>>
> >>> That's what I understood from his email.
> >>>
> >>>> I don't
> >>>> understand the change Sudeep is referring to.
> >>
> >> Actually there is no impact with the change Sudeep is referring to. It
> >> is for ACPI, we are DT based. Confirmed with Jeremy.
> >>
> >
> > No, it will change for DT. The aim is to be consistent irrespective of
> > h/w or f/w description(i.e ADCPI or DT)
>
> What will happen with the code using topology_physical_package_id ?
>
> drivers/acpi/processor_thermal.c: int id = topology_physical_package_id(cpu);
> drivers/acpi/processor_thermal.c: if (topology_physical_package_id(i) == id)
> drivers/acpi/processor_thermal.c: if (topology_physical_package_id(i) ==
> drivers/acpi/processor_thermal.c: topology_physical_package_id(cpu))
>

ACPI and hence will have right notion of package.

> drivers/block/mtip32xx/mtip32xx.c: topology_physical_package_id(cpumask_first(node_mask)),
>

Not sure if it was ever used on ARM/ARM64

> drivers/cpufreq/arm_big_little.c: return topology_physical_package_id(cpu);

Yes this is main affected driver. I don't think it's used by any ARM64
platform anymore. This is one of the reason I divorced SCPI driver from
this recently. ARM32 may still retain old definition of package_id(not
sure, depends if anyone as need to change that and maintainers view on
that). If not, we need to fix this driver along with the code changing
the definition.

>
> drivers/crypto/qat/qat_common/adf_common_drv.h: return topology_physical_package_id(smp_processor_id());
> drivers/crypto/virtio/virtio_crypto_common.h: node = topology_physical_package_id(cpu);
>

x86 specific and never assumed cluster id.

> kernel/events/core.c: event_pkg = topology_physical_package_id(event_cpu);
> kernel/events/core.c: local_pkg = topology_physical_package_id(local_cpu);
>

Generic and hence never assumed cluster id.

--
Regards,
Sudeep

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