Re: [PATCH v2 1/3] PCI / ACPI: Use cached ACPI device state to get PCI device power state

Mika Westerberg
2019-06-24T10:58:38Z

On Fri, Jun 21, 2019 at 01:56:49PM +0200, Rafael J. Wysocki wrote:
> On Tue, Jun 18, 2019 at 6:19 PM Mika Westerberg
> <mika.westerberg@linux.intel.com> wrote:
> >
>
> Actually, to start with, you can say that the ACPI power state
> returned by acpi_device_get_power() may depend on the configuration of
> ACPI power resources in the system which may change at any time after
> acpi_device_get_power() has returned, unless the reference counters of
> the ACPI power resources in question are set to prevent that from
> happening. Thus it is invalid to use acpi_device_get_power() in
> acpi_pci_get_power_state() the way it is done now and the value of the
> power.state field in the corresponding struct acpi_device object
> (which reflects the ACPI power resources reference counting, among
> other things) should be used instead.
>
> Then you can describe the particular issue below as an example.
>
> IMO that would explain the rationale better here.

Thanks! I'll update the changelog accordingly.