From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: joeyli <jlee@suse.com>
Cc: Matt Fleming <matt@console-pimps.org>, "H. Peter Anvin" <hpa@zytor.com>,
        Alessandro Zummo <a.zummo@towertech.it>,
        Matthew Garrett <matthew.garrett@nebula.com>, Elliott@hp.com,
        samer.el-haj-mahmoud@hp.com, Oliver Neukum <oneukum@suse.de>,
        werner@suse.com, trenn@suse.de, JBeulich@suse.com,
        linux-kernel@vger.kernel.org, rtc-linux@googlegroups.com,
        x86@kernel.org,
        "linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>,
        linux-acpi@vger.kernel.org, Borislav Petkov <bp@suse.de>
Subject: Re: [RFT][PATCH] ACPI / init: Run acpi_early_init() before efi_enter_virtual_mode() (was: Re: [RFC PATCH 00/14] Support timezone of ACPI TAD and EFI TIME)
Date: Tue, 14 Jan 2014 17:50:07 +0100
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On Tuesday, January 14, 2014 12:09:08 PM joeyli wrote:
> 於 日，2014-01-12 於 01:30 +0100，Rafael J. Wysocki 提到：
> > OK
> > 
> > I don't see any adverse effects of the patch below on a couple of my
> > test
> > boxes, but (a) they are Intel-based and (b) they are non-EFI, so it
> > would be
> > good to give it a go on as many machines as reasonably possible.
> > 
> > Thanks,
> > Rafael
> > 
> > ---
> > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > Subject: ACPI / init: Run acpi_early_init() before
> > efi_enter_virtual_mode()
> > 
> > According to Matt Fleming, if acpi_early_init() was executed befpre
> > efi_enter_virtual_mode(), the EFI initialization could benefit from
> > it, so make that happen.
> > 
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> > ---
> >  init/main.c |    2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > Index: linux-pm/init/main.c
> > ===================================================================
> > --- linux-pm.orig/init/main.c
> > +++ linux-pm/init/main.c
> > @@ -615,6 +615,7 @@ asmlinkage void __init start_kernel(void
> >         calibrate_delay();
> >         pidmap_init();
> >         anon_vma_init();
> > +       acpi_early_init();
> >  #ifdef CONFIG_X86
> >         if (efi_enabled(EFI_RUNTIME_SERVICES))
> >                 efi_enter_virtual_mode();
> > @@ -641,7 +642,6 @@ asmlinkage void __init start_kernel(void
> >  
> >         check_bugs();
> >  
> > -       acpi_early_init(); /* before LAPIC and SMP init */
> >         sfi_init_late();
> >  
> >         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
> > 
> > 
> > 
> 
> This patch works to me on Acer Gateway Z5WT2 UEFI notebook and Intel
> UEFI development board.
> 
> Does it possible move acpi_early_init() to before timekeeping_init()?

We can do that if it doesn't cause any problems to happen.

Please resubmit your patch with a changelog and we'll ask everyone to try it.

Thanks!

> The position is also before efi_enter_virtual_mode() and that will be
> useful for parsing ACPI TAD to set system clock:
> 
> diff --git a/init/main.c b/init/main.c
> index febc511..b6d93c8 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -565,6 +565,7 @@ asmlinkage void __init start_kernel(void)
>         init_timers();
>         hrtimers_init();
>         softirq_init();
> +       acpi_early_init();
>         timekeeping_init();
>         time_init();
>         sched_clock_postinit();
> @@ -641,7 +642,6 @@ asmlinkage void __init start_kernel(void)
>  
>         check_bugs();
>  
> -       acpi_early_init(); /* before LAPIC and SMP init */
>         sfi_init_late();
>  
>         if (efi_enabled(EFI_RUNTIME_SERVICES)) {
> 
> 
> Thanks a lot!
> Joey Lee
> 

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