Re: [PATCH 5/7] platform/x86: fujitsu-laptop: do not update ACPI device power status

From	Jonathan Woithe <jwoithe@just42.net>
Newsgroups	linux.kernel
Subject	Re: [PATCH 5/7] platform/x86: fujitsu-laptop: do not update ACPI device power status
Date	2017-06-23 02:20 +0200
Message-ID	<tVkul-3lB-1@gated-at.bofh.it> (permalink)
References	<tSRmN-3Ii-3@gated-at.bofh.it> <tSRmO-3Ii-11@gated-at.bofh.it> <tUUgx-2Hl-1@gated-at.bofh.it> <tVhwv-1xP-33@gated-at.bofh.it> <tVkaZ-2ZS-1@gated-at.bofh.it>
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On Thu, Jun 22, 2017 at 04:58:43PM -0700, Darren Hart wrote:
> On Thu, Jun 22, 2017 at 11:02:35PM +0200, Micha?? K??pie?? wrote:
> > > On Fri, Jun 16, 2017 at 06:40:56AM +0200, Micha?? K??pie?? wrote:
> > > > Calling acpi_bus_update_power() for ACPI devices FUJ02B1 and FUJ02E3 is
> > > > pointless as they are not power manageable (neither _PS0 nor _PR0 is
> > > > defined for any of them), which causes their power state to be inherited
> > > > from their parent devices.  Given the ACPI paths of these two devices
> > > > (\_SB.PCI0.LPCB.FJEX, \_SB.FEXT), their parent devices are also not
> > > > power manageable.  These parent devices will thus have their power state
> > > > initialized to ACPI_STATE_D0, which in turn causes the power state for
> > > > both FUJ02B1 and FUJ02E3 to always be ACPI_STATE_D0 ("on").
> > > > 
> > > 
> > > How confident are we that all implementations of these two ACPI devices lack
> > > _PS0 and _PR0 ?
> > 
> > I looked at DSDT dumps of four different Fujitsu laptops released in the
> > past ten years or so for which at least one of these two ACPI devices is
> > present and found no traces of either of these methods being defined for
> > them.  I do not think we have a way of ensuring that the above holds
> > true for every other model out there, but I will point out that
> > fujitsu-laptop is the only user of acpi_bus_update_power() outside of
> > drivers/acpi.
> 
> OK, thanks. Queueing to testing.

Thanks.  In case it was missed, I supplied my reviewed-by message and
sign-off in an earlier post.

Regards
  jonathan

Thread

Re: [PATCH 5/7] platform/x86: fujitsu-laptop: do not update ACPI  device power status Darren Hart <dvhart@infradead.org> - 2017-06-21 22:20 +0200
  Re: [PATCH 5/7] platform/x86: fujitsu-laptop: do not update ACPI  device power status Michał Kępień <kernel@kempniu.pl> - 2017-06-22 23:10 +0200
    Re: [PATCH 5/7] platform/x86: fujitsu-laptop: do not update ACPI  device power status Darren Hart <dvhart@infradead.org> - 2017-06-23 02:00 +0200
      Re: [PATCH 5/7] platform/x86: fujitsu-laptop: do not update ACPI  device power status Jonathan Woithe <jwoithe@just42.net> - 2017-06-23 02:20 +0200
        Re: [PATCH 5/7] platform/x86: fujitsu-laptop: do not update ACPI  device power status Darren Hart <dvhart@infradead.org> - 2017-06-23 08:00 +0200

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