Re: [PATCH] platform/x86: thinkpad_acpi: Accept flat mode for type 4 multi mode status

[Benjamin Berg <bberg@redhat.com>]

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On Tue, 2017-11-14 at 18:58 +0200, Andy Shevchenko wrote:
> On Tue, Nov 14, 2017 at 6:14 PM, Benjamin Berg <bberg@redhat.com>
> wrote:
> > On the X1 Yoga 2nd Generation and most likely other notebooks the
> > FLAT
> > mode is reported. Decode it correctly rather than warning about an
> > unexpected multi mode status to be reported.
> 
> If we can't check on all available hardware, better to avoid "doing
> for all" fixes.
> I suppose DMI match can help here.

The documentation I saw suggests that the flat mode cannot be detected
by machines reporting a multi mode status of type 4. This is why the
original patch excluded the FLAT mode in the list of valid modes on
those devices.

I think it is safe to simply assume that all laptops reporting type 4
can actually detect the flat state. Doing so will not affect actual
state reporting on machines that may not be able to detect it. And I
don't think that the information whether the flat state can be detected
or not is interesting enough to bother with DMI matches.

Benjamin

> It would be nice to hear from Henrique and others as well.
> 
> 
> >         case 4:
> > -               valid_modes = TP_ACPI_MULTI_MODE_LAPTOP |
> > -                             TP_ACPI_MULTI_MODE_TABLET |
> > -                             TP_ACPI_MULTI_MODE_STAND |
> > -                             TP_ACPI_MULTI_MODE_TENT;
> > -               break;
> 
> The common practice is to put
> /* fallthrough */
> instead.
> 
> >         case 5:
> > +               /* In mode 4, FLAT is not specified as a valid
> > mode. However,
> > +                * it can be seen at least on the X1 Yoga 2nd
> > Generation.
> > +                */
> 
> We don't use network subsystem style of comments.
> 
> >                 valid_modes = TP_ACPI_MULTI_MODE_LAPTOP |
> >                               TP_ACPI_MULTI_MODE_FLAT |
> >                               TP_ACPI_MULTI_MODE_TABLET |
> >                               TP_ACPI_MULTI_MODE_STAND |
> >                               TP_ACPI_MULTI_MODE_TENT;
> >                 break;
> 
> 

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