linux-kernel - Re: [update][PATCH v10 06/21] ACPI / sleep: Introduce CONFIG_ACPI_GENERIC

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Message-ID: <16235723.xVJ1Rfp9tM@vostro.rjw.lan>
Date:	Tue, 17 Mar 2015 15:33:30 +0100
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Hanjun Guo <guohanjun@...wei.com>
Cc:	Hanjun Guo <hanjun.guo@...aro.org>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will.deacon@....com>,
	Olof Johansson <olof@...om.net>,
	Grant Likely <grant.likely@...aro.org>,
	Lorenzo Pieralisi <Lorenzo.Pieralisi@....com>,
	Arnd Bergmann <arnd@...db.de>,
	Mark Rutland <mark.rutland@....com>,
	Graeme Gregory <graeme.gregory@...aro.org>,
	Sudeep Holla <Sudeep.Holla@....com>,
	Jon Masters <jcm@...hat.com>,
	Marc Zyngier <marc.zyngier@....com>,
	Mark Brown <broonie@...nel.org>,
	Robert Richter <rric@...nel.org>,
	Timur Tabi <timur@...eaurora.org>,
	Ashwin Chaugule <ashwinc@...eaurora.org>,
	suravee.suthikulpanit@....com, linux-acpi@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linaro-acpi@...ts.linaro.org,
	Tomasz Nowicki <tomasz.nowicki@...aro.org>,
	Zhangdianfang <zhangdianfang@...wei.com>
Subject: Re: [update][PATCH v10 06/21] ACPI / sleep: Introduce CONFIG_ACPI_GENERIC_SLEEP

On Tuesday, March 17, 2015 12:10:02 PM Hanjun Guo wrote:
> On 2015/3/17 11:23, Rafael J. Wysocki wrote:
> > On Tuesday, March 17, 2015 10:36:47 AM Hanjun Guo wrote:
> >> On 2015/3/17 10:28, Rafael J. Wysocki wrote:
> >>> On Tuesday, March 17, 2015 09:08:45 AM Hanjun Guo wrote:
> >>>> On 2015/3/17 7:15, Rafael J. Wysocki wrote:
> >>>>> On Monday, March 16, 2015 08:14:52 PM Hanjun Guo wrote:
> >>>>>> On 2015年03月14日 05:49, Rafael J. Wysocki wrote:
> >>>>>>> On Friday, March 13, 2015 04:14:29 PM Hanjun Guo wrote:
> >>>> [...]
> >>>>>>>> diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
> >>>>>>>> index 074e52b..e8728d7 100644
> >>>>>>>> --- a/arch/ia64/Kconfig
> >>>>>>>> +++ b/arch/ia64/Kconfig
> >>>>>>>> @@ -10,6 +10,7 @@ config IA64
> >>>>>>>>   	select ARCH_MIGHT_HAVE_PC_SERIO
> >>>>>>>>   	select PCI if (!IA64_HP_SIM)
> >>>>>>>>   	select ACPI if (!IA64_HP_SIM)
> >>>>>>>> +	select ACPI_GENERIC_SLEEP if ACPI
> >>>>>>>>   	select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
> >>>>>>>>   	select HAVE_UNSTABLE_SCHED_CLOCK
> >>>>>>>>   	select HAVE_IDE
> >>>>>>>> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> >>>>>>>> index b7d31ca..9804431 100644
> >>>>>>>> --- a/arch/x86/Kconfig
> >>>>>>>> +++ b/arch/x86/Kconfig
> >>>>>>>> @@ -22,6 +22,7 @@ config X86_64
> >>>>>>>>   ### Arch settings
> >>>>>>>>   config X86
> >>>>>>>>   	def_bool y
> >>>>>>>> +	select ACPI_GENERIC_SLEEP if ACPI
> >>>>>>> One more nit.  If you did
> >>>>>>>
> >>>>>>> +	select ACPI_GENERIC_SLEEP if ACPI_SLEEP
> >>>>>>>
> >>>>>>> here (and above for ia64), you'd avoid having to make ACPI_SLEEP
> >>>>>>> depend on ACPI_GENERIC_SLEEP which goes somewhat backwards.
> >>>>>> In sleep.c,
> >>>>>>
> >>>>>> #ifdef CONFIG_ACPI_SLEEP
> >>>>>> acpi_target_system_state()
> >>>>>> {
> >>>>>> }
> >>>>>> #endif
> >>>>>>
> >>>>>> and CONFIG_ACPI_SLEEP depends on SUSPEND || HIBERNATION,
> >>>>>> which one of them will be enabled on ARM64 so ACPI_SLEEP
> >>>>>> will also enabled too.
> >>>>>>
> >>>>>> So if we
> >>>>>>
> >>>>>> +select ACPI_GENERIC_SLEEP if ACPI_SLEEP
> >>>>>>
> >>>>>> and
> >>>>>>
> >>>>>> +acpi-$(CONFIG_ACPI_GENERIC_SLEEP) += sleep.o
> >>>>>>
> >>>>>> it will lead to errors for acpi_target_system_state() that
> >>>>>> is declared but not defined, so I will keep the code as
> >>>>>> it is, what do you think?
> >>>>> No, we need to hash this out.  Having two different Kconfig options meaning
> >>>>> almost the same thing (ACPI_SLEEP and ACPI_GENERIC_SLEEP) is beyond ugly.
> >>>>>
> >>>>> Do you need ACPI_SLEEP on ARM64 at all?
> >>>> No, at least for now we don't need it, the spec for sleep is not ready for
> >>>> ARM64 arch, so ACPI_SLEEP will not work at all on ARM64.
> >>> Well, so what about selecting ACPI_SLEEP from the architectures that use it?
> >> Do you mean remove CONFIG_ACPI_GENERIC_SLEEP and
> >>
> >> +acpi-$(CONFIG_ACPI_SLEEP) += sleep.o
> >>
> >> as well (also need to remove duplicate #ifdef CONFIG_ACPI_SLEEP in sleep.c if
> >> we doing so)?
> > Well, almost.  There is one problem with that, becuase sleep.c contains code
> > outside of the ACPI_SLEEP-dependent blocks.  That code is used for powering
> > off ACPI platforms.
> >
> > I guess you don't want that code on ARM too, right?
> 
> Yes, you are right.
> 
> >
> > Perhaps we can use ACPI_REDUCED_HARDWARE_ONLY for that?  ARM64 will be the
> 
> Sorry, I can't fully understand your intention here, could you please
> explain it more?
> 
> Let me guess a little bit. Do you mean use ACPI_REDUCED_HARDWARE_ONLY for
> powering off ACPI platforms? if so, I guess it's not a good idea, ACPI spec
> only says that S4BIOS is not supported on HW-reduced ACPI platforms, S5
> has no such limitation, if I miss something here, please let me know.

OK, so in your current patch, please replace ACPI_GENERIC_SLEEP with
ACPI_SYSTEM_POWER_STATES_SUPPORT and all should be clear.


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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