linux-kernel - RE: [PATCH][RFC v3] ACPI / PM: Fix poweroff issue on HW-full platforms without

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Date:	Mon, 7 Mar 2016 15:49:13 +0000
From:	"Chen, Yu C" <yu.c.chen@...el.com>
To:	"Rafael J. Wysocki" <rafael@...nel.org>
CC:	ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
	"x86@...nel.org" <x86@...nel.org>,
	"linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <lenb@...nel.org>,
	Matt Fleming <matt@...eblueprint.co.uk>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	"Zhang, Rui" <rui.zhang@...el.com>
Subject: RE: [PATCH][RFC v3] ACPI / PM: Fix poweroff issue on HW-full
 platforms without _S5

Hi Rafael,


> -----Original Message-----
> From: rjwysocki@...il.com [mailto:rjwysocki@...il.com] On Behalf Of
> Rafael J. Wysocki
> Sent: Monday, March 07, 2016 9:19 PM
> To: Chen, Yu C
> Cc: ACPI Devel Maling List; x86@...nel.org; linux-efi@...r.kernel.org; Linux
> Kernel Mailing List; linux-pm@...r.kernel.org; Rafael J. Wysocki; Len Brown;
> Matt Fleming; Thomas Gleixner; Ingo Molnar; H. Peter Anvin; Zhang, Rui
> Subject: Re: [PATCH][RFC v3] ACPI / PM: Fix poweroff issue on HW-full
> platforms without _S5
> 
> On Mon, Mar 7, 2016 at 3:50 AM, Chen Yu <yu.c.chen@...el.com> wrote:
> > The problem is Linux registers pm_power_off = efi_power_off only if we
> > are in hardware reduced mode. Actually, what we also want is to do
> > this when ACPI S5 is simply not supported on non-legacy platforms.
> > That should handle both the HW reduced mode, and the HW-full mode
> > where the DSDT fails to supply an _S5 object.
> >
> > This patch fixes this issue by introducing a new flag acpi_no_s5 which
> > indicates the non-existence of _S5. The initial state of acpi_no_s5 is
> > false and probed in acpi_sleep_init, then we'll later see the updated
> > value in efi_poweroff_required, according to which we can set
> > pm_power_off to efi_power_off in efi_shutdown_init, if no other
> pm_power_off available.
> >
> > Suggested-by: Len Brown <len.brown@...el.com>
> > Signed-off-by: Chen Yu <yu.c.chen@...el.com>
> > ---
> > v3:
> >  - Only assign pm_power_off to efi_power_off when there are no
> >    other pm_power_off registered at that time, in case other
> >    commponents would like to customize their own implementation.
> > ---
> > v2:
> >  - Convert the acpi_no_s5 to a global bool variable in sleep.c and
> >    add a declaration to include/linux/acpi.h.
> > ---
> >  arch/x86/platform/efi/quirks.c | 2 +-
> >  drivers/acpi/sleep.c           | 8 ++++++++
> >  include/linux/acpi.h           | 1 +
> >  3 files changed, 10 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/x86/platform/efi/quirks.c
> > b/arch/x86/platform/efi/quirks.c index 2d66db8..0d4186b 100644
> > --- a/arch/x86/platform/efi/quirks.c
> > +++ b/arch/x86/platform/efi/quirks.c
> > @@ -295,5 +295,5 @@ bool efi_reboot_required(void)
> >
> >  bool efi_poweroff_required(void)
> >  {
> > -       return !!acpi_gbl_reduced_hardware;
> > +       return acpi_gbl_reduced_hardware || (acpi_no_s5 &&
> > + !pm_power_off);
> 
> What if CONFIG_ACPI is not set here?
> 
If CONFIG_ACPI is not set, this file would not be compiled,
because CONFIG_EFI depends on CONFIG_ACPI.