Re: [PATCH v1 5/7] surface: surface3_power: Use ACPI_COMPANION() directly

Rafael J. Wysocki
2021-10-12T19:11:29Z

On Tue, Oct 12, 2021 at 8:21 PM Maximilian Luz <luzmaximilian@gmail.com> wrote:
>
> On 10/12/21 19:46, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rafael@kernel.org>
> >
> > The ACPI_HANDLE() macro is a wrapper arond the ACPI_COMPANION()
> > macro and the ACPI handle produced by the former comes from the
> > ACPI device object produced by the latter, so it is way more
> > straightforward to evaluate the latter directly instead of passing
> > the handle produced by the former to acpi_bus_get_device().
> >
> > Modify mshw0011_notify() accordingly (no intentional functional
> > impact).
> >
> > Signed-off-by: Rafael J. Wysocki <rafael@kernel.org>
>
> Looks mostly good to me, small comment/question inline.
>
> > ---
> > drivers/platform/surface/surface3_power.c | 9 ++++-----
> > 1 file changed, 4 insertions(+), 5 deletions(-)
> >
> > Index: linux-pm/drivers/platform/surface/surface3_power.c
> > ===================================================================
> > --- linux-pm.orig/drivers/platform/surface/surface3_power.c
> > +++ linux-pm/drivers/platform/surface/surface3_power.c
> > @@ -160,15 +160,14 @@ mshw0011_notify(struct mshw0011_data *cd
> > {
> > union acpi_object *obj;
> > struct acpi_device *adev;
> > - acpi_handle handle;
> > unsigned int i;
> >
> > - handle = ACPI_HANDLE(&cdata->adp1->dev);
> > - if (!handle || acpi_bus_get_device(handle, &adev))
> > + adev = ACPI_COMPANION(&cdata->adp1->dev);
> > + if (!adev)
> > return -ENODEV;
>
> Do we need to get the ACPI device (adev) here? To me it looks like only
> its handle is actually used so why not keep ACPI_HANDLE() and remove the
> acpi_bus_get_device() call instead?

It actually doesn't really matter, but you're right,
acpi_bus_get_device() is simply redundant here, so ACPI_HANDLE() is
sufficient.

I'll send a v2 of this one.

> >
> > - obj = acpi_evaluate_dsm_typed(handle, &mshw0011_guid, arg1, arg2, NULL,
> > - ACPI_TYPE_BUFFER);
> > + obj = acpi_evaluate_dsm_typed(adev->handle, &mshw0011_guid, arg1, arg2,
> > + NULL, ACPI_TYPE_BUFFER);
> > if (!obj) {
> > dev_err(&cdata->adp1->dev, "device _DSM execution failed\n");
> > return -ENODEV;
> >
> >
> >
>
> Regards,
> Max