linux-kernel - Re: [PATCH v2 1/2] ACPI: platform: Ignore SMB0001 only when it has resources

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Message-ID: <CAJZ5v0iKLtQpUnhMqB6zgwbURXGFZkje5rNORS9MLqYN=13nWg@mail.gmail.com>
Date:   Fri, 23 Jun 2023 16:43:55 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     "Rafael J. Wysocki" <rafael@...nel.org>,
        linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-i2c@...r.kernel.org, acpica-devel@...ts.linuxfoundation.org,
        Len Brown <lenb@...nel.org>,
        Andi Shyti <andi.shyti@...nel.org>,
        Robert Moore <robert.moore@...el.com>,
        Michael Brunner <michael.brunner@...tron.com>
Subject: Re: [PATCH v2 1/2] ACPI: platform: Ignore SMB0001 only when it has resources

On Thu, Jun 22, 2023 at 8:19 PM Andy Shevchenko
<andriy.shevchenko@...ux.intel.com> wrote:
>
> On Thu, Jun 22, 2023 at 05:53:13PM +0200, Rafael J. Wysocki wrote:
> > On Wed, Jun 21, 2023 at 5:16 PM Andy Shevchenko
> > <andriy.shevchenko@...ux.intel.com> wrote:
> > >
> > > After switching i2c-scmi driver to be a plaform one, it stopped
> >
> > "platform"
> >
> > > being enumerated on number of Kontron platforms, because it's
> > > listed in the forbidden_id_list.
> > >
> > > To resolve the situation, split the list to generic one and
> > > another that holds devices that has to be skipped if and only
> >
> > "have"
> >
> > > if they have bogus resources attached (_CRS method returns some).
>
> Thanks for the typo fixes!
>
> ...
>
> > > +static const struct acpi_device_id forbidden_id_with_resourses[] = {
> >
> > I don't quite like this name and the driver_data field could be used
> > to indicate the need to check the resources.
>
> Okay, something like
>
> /* Check if the device has resources provided by _CRS method */
> #define ACPI_PLATFORM_CHECK_RES         BIT(0)
>
> ?

Could be, but this is specific to forbidden_ids_list[].  Maybe
ACPI_ALLOW_WO_RESOURCES or similar.

> > > +       {"SMB0001",  0},        /* ACPI SMBUS virtual device */
> > > +       { }
> > > +};
>
> ...
>
> > > +static int acpi_platform_resource_count(struct acpi_resource *ares, void *data)
> > > +{
> > > +       int *count = data;
> > > +
> > > +       *count = *count + 1;
> >
> > Why not (*count)++?
>
> Can be that way, I just copied'n'pasted from the existing code.
>
> > > +       return 1;
> > > +}

BTW, this doesn't need to increment the count even.  It could just
terminate the walk on the first valid resource found and tell the
caller to return true in that case.