Re: [PATCH v2] ACPI / LPSS: Ignore acpi_device_fix_up_power() return value

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On Wed, Dec 12, 2018 at 02:04:32PM +0100, Rafael J. Wysocki wrote:
> On Sun, Dec 9, 2018 at 3:12 PM Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
> >
> > Hi,
> >
> > On 09-12-18 06:55, Andy Shevchenko wrote:
> > > On Sat, Dec 08, 2018 at 01:59:24PM +0100, Hans de Goede wrote:
> > >> Ignore acpi_device_fix_up_power() return value. If we return an error
> > >> we end up with acpi_default_enumeration() still creating a platform-
> > >> device for the device and we end up with the device still being used
> > >> but without the special LPSS related handling which is not useful.
> > >>
> > >> Specicifically ignoring the error fixes the touchscreen no longer
> > >> working after a suspend/resume on a Prowise PT301 tablet.
> > >
> > > Hmm... Sounds like a hammer for a rather rare cases.
> > > Wouldn't be better to have DMI based matching quirk then do it for everyone?
> >
> > As I tried to explain in the commit message making acpi_lpss_create_device()
> > fail and thus failing the acpi_scan_handler lpss_handler.attach method does
> > not really gain us anything. This will make drivers/acpi/scan.c fall back
> > to the acpi_default_enumeration() function, calling acpi_create_platform_device()
> > so a platform_device will still be created, the driver for the LPSS function
> > will still bind to it, etc. Also at this point we have already called
> > dev_desc->setup(), registered the clock-device, etc. None of which we undo.
> >
> > All causing acpi_lpss_create_device() to fail does is remove the special handling
> > on suspend/resume mainly skipping acpi_lpss_save/restore_ctx, which really
> > does not gain us anything.
> >
> > So my reason for taking the big hammer approach here is that exiting with
> > an error at this point really is not helpful.
> 
> This sounds fair enough for me.  Andy, do you agree?

Yes.

-- 
With Best Regards,
Andy Shevchenko





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