Re: [PATCH v3] ACPI: bus: Use OF match data for PRP0001 matched devices

[Kartik Rajput]

On 12/01/26 03:31, Sakari Ailus wrote:
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>
>
> Hi Rafael, Andy,
>
> On Fri, Jan 09, 2026 at 10:11:26PM +0100, Rafael J. Wysocki wrote:
> > On Fri, Jan 9, 2026 at 6:02 PM Andy Shevchenko
> > <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
> > > On Fri, Jan 09, 2026 at 01:29:59PM +0200, Sakari Ailus wrote:
> > > > On Fri, Jan 09, 2026 at 01:05:52PM +0200, Andy Shevchenko wrote:
> > > > > On Fri, Jan 09, 2026 at 11:13:02AM +0100, Mika Westerberg wrote:
> > > > > > On Fri, Jan 09, 2026 at 03:23:58PM +0530, Kartik Rajput wrote:
> > > > > > > During pre-production development, drivers may provide both ACPI and OF
> > > > > > > match tables while a formal ACPI HID for the device is not yet
> > > > > > > allocated. Such devices are enumerated via PRP0001. In this case,
> > > > > > > acpi_device_get_match_data() consults only the driver’s ACPI match table
> > > > > > > and returns NULL, even though the device was successfully matched via
> > > > > > > PRP0001.
> > > > > > >
> > > > > > > This behavior also risks breaking existing PRP0001 setups if a driver
> > > > > > > later gains an ACPI HID, as the presence of an ACPI match table changes
> > > > > > > the match-data lookup path.
> > > > > > >
> > > > > > > Explicitly detect PRP0001 and fetch match data from the driver's
> > > > > > > OF match table via acpi_of_device_get_match_data().
> > >
> > > ...
> > >
> > > > > > >          const struct acpi_device_id *acpi_ids = dev->driver->acpi_match_table;
> > > > > > > +       struct acpi_device *adev = ACPI_COMPANION(dev);
> > > > > > >          const struct acpi_device_id *match;
> > > > > > >
> > > > > > > -       if (!acpi_ids)
> > > > > > > +       if (!adev)
> > > > > > > +               return NULL;
> > > > > > > +
> > > > > > > +       if (!strcmp(acpi_device_hid(adev), ACPI_DT_NAMESPACE_HID))
> > > > > > >                  return acpi_of_device_get_match_data(dev);
> > > > >
> > > > > On top of what Mika asked, shouldn't we check CID as well? Theoretically it's
> > > > > possible that some device may have HID "blablabla" and CID PRP0001, I don't
> > > > > remember what documentation says about this case, though.
> > > >
> > > > According to Documentation/firmware-guide/acpi/enumeration.rst PRP0001 is
> > > > also valid for _CID. So yes, I think this should be checked as well -- I'd
> > > > loop over the &device->pnp.ids list.
> > >
> > > Yeah, but if we have a device with
> > >
> > > HID "blablabla"
> > > CID "PRP0001"
> > >
> > > and at the same time the driver has ACPI ID listed, we should probably use that
> > > one as HID should have higher weight for matching. Logic here is not just as simple
> > > as looping over pnp.ids how I see it.
> >
> > Right.
> >
> > What about:
> >
> > if (acpi_ids) {
> >         match = acpi_match_device(acpi_ids, dev);
> >         if (match)
> >                 return (const void *)match->driver_data;
> > }
> > return acpi_of_device_get_match_data(dev);
>
> That would mean that any ACPI (or PNP) ID has priority over compatible
> matching, wouldn't it? AFAIU the documentation says effectively that
> _HID/_CID priority is upheld, whether matching with PRP0001 or without.
>
> --
> Regards,
>
> Sakari Ailus


Hi Rafael, Sakari, Andy,

Since we seem to be using __acpi_match_device() match the device.
What if we directly utilise __acpi_match_device() here?

Something like:

	if (!__acpi_match_device(adev, acpi_ids, of_ids, &acpi_id, &of_id))
		return NULL;

	if (acpi_id)
		return (const void *)acpi_id->driver_data;

	if (of_id)
		return of_id->data;

	return NULL;

Then, we can also remove acpi_of_device_get_match_data()?

Thanks,
Kartik