Re: [PATCH] x86/ACPI: Make Sony Vaio Z1 series to use "reboot=pci"default

[Lan Tianyu]

On 10/25/2013 06:53 PM, Ingo Molnar wrote:
> * tianyu.lan@xxxxxxxxx <tianyu.lan@xxxxxxxxx> wrote:
>
> > From: Lan Tianyu <tianyu.lan@xxxxxxxxx>
> >
> > Sony Vaio Z1 series require "reboot=pci" for reboot and power off.
> > This patch is to add them machines to quirk table and set pci reboot
> > default.
> >
> > Reference: https://bugzilla.kernel.org/show_bug.cgi?id=61721
> > Reported-and-tested-by: Adam Williamson <awilliam@xxxxxxxxxx>
> > Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx>
> > ---
> >   arch/x86/kernel/reboot.c |    8 ++++++++
> >   1 file changed, 8 insertions(+)
> >
> > diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
> > index 7e920bf..083ade7 100644
> > --- a/arch/x86/kernel/reboot.c
> > +++ b/arch/x86/kernel/reboot.c
> > @@ -382,6 +382,14 @@ static struct dmi_system_id __initdata reboot_dmi_table[] = {
> >   			DMI_MATCH(DMI_PRODUCT_NAME, "C6100"),
> >   		},
> >   	},
> > +	{	/* Handle problems with rebooting on Sony Vaio Z1 series*/
> > +		.callback = set_pci_reboot,
> > +		.ident = "Sony Vaio Z1",
> > +		.matches = {
> > +		DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
> > +		DMI_MATCH(DMI_PRODUCT_NAME, "VPCZ1"),
> > +		},
> > +	},
>
> This is becoming somewhat endemic - do we know _why_ the ACPI reboot
> method does not work?
>
> We reworked the x86 reboot sequence 2.5 years agom, in:
>
>   commit 660e34cebf0a11d54f2d5dd8838607452355f321
>   Author: Matthew Garrett <mjg@xxxxxxxxxx>
>   Date:   Mon Apr 4 13:55:05 2011 -0400
>
>      x86: Reorder reboot method preferences
>
>      We have a never ending stream of 'reboot quirks' for new boxes
>      that will not reboot properly under Linux (they will hang on
>      reboot).
>
>      The reason is widespread 'Windows compatible' assumption of modern
>      x86 hardware, which expects the following reboot sequence:
>
>       - hitting the ACPI reboot vector (if available)
>       - trying the keyboard controller
>       - hitting the ACPI reboot vector again
>       - then giving the keyboard controller one last go
>
>      This sequence expectation gets more and more embedded in modern
>      hardware, which often lacks a keyboard controller and may even
>      lock up if the legacy io ports are hit - and which hardware is
>      often not tested with Linux during development.
>
>      The end result is that reboot works under Windows-alike OSs but not
>      under Linux.
>
>      Rework our reboot process to meet this hardware externality a little
>      better and match this assumption of newer x86 hardware.
>
>      In addition to the ACPI,kbd,ACPI,kbd sequence we'll still fall
>      through to attempting a legacy triple fault if nothing else
>      works - and keep trying that and the kbd reset.
>
>      [...]
>
> Do we know why reboot apparently works quickly enough on Windows on
> this laptop, but not under Linux? Does Windows use the ACPI reboot
> method? If yes, does it use a different pattern?
>
> Is it all perhaps virtualization or IRQ routing related?
>
> I.e. we really need a real analysis here, not just a quirk!

Sorry about this. Will do some analyses.

> Thanks,
>
> 	Ingo

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