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Date:   Wed, 17 Apr 2019 21:17:02 +0200
From:   Ingo Molnar <mingo@kernel.org>
To:     Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc:     "Prakhya, Sai Praneeth" <sai.praneeth.prakhya@intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Daniel Drake <drake@endlessm.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Borislav Petkov <bp@alien8.de>,
        Thomas Gleixner <tglx@linutronix.de>,
        Linux Kernel <linux-kernel@vger.kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Jian-Hong Pan <jian-hong@endlessm.com>,
        Matt Fleming <matt@codeblueprint.co.uk>,
        linux-efi <linux-efi@vger.kernel.org>,
        "Brown, Len" <len.brown@intel.com>,
        "linux-tip-commits@vger.kernel.org" 
        <linux-tip-commits@vger.kernel.org>,
        Endless Linux Upstreaming Team <linux@endlessm.com>
Subject: Re: EFI reboot vs. ACPI reboot (was: Re: [tip:x86/urgent]
 x86/reboot, efi: Use EFI reboot for Acer TravelMate X514-51T)
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* Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:

> On Wed, 17 Apr 2019 at 11:23, Ingo Molnar <mingo@kernel.org> wrote:
> >
> >
> > * Prakhya, Sai Praneeth <sai.praneeth.prakhya@intel.com> wrote:
> >
> > > I will ask around internally to check if it is a good idea to make EFI
> > > reboot the default method when the machine is booted in EFI mode.
> >
> > Or whether there's some robust signature that indicates "modern EFI
> > system where EFI reboot is the primary method"?
> >
> > Major EFI version or ACPI version or such?
> >
> 
> I am actually at Microsoft right now, and I managed to get
> clarification on how Windows deals with this: Windows will attempt to
> use ACPI reboot first, and will only attempt to use anything else if
> that fails. EFI reset is actually its least preferred option, and so
> it is highly likely that it is untested on most of the shipping x86
> hardware if any of the other methods work.
> 
> So let's not touch this.

Agreed and that's really useful information, thanks!

	Ingo