linux-kernel - Re: [PATCH][RFC v2] PCI: Workaround to enable poweroff on Mac Pro 11

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Date:   Fri, 19 Aug 2016 16:01:59 +0800
From:   Chen Yu <yu.c.chen@...el.com>
To:     Lukas Wunner <lukas@...ner.de>
Cc:     linux-pci@...r.kernel.org, Bjorn Helgaas <bhelgaas@...gle.com>,
        linux-kernel@...r.kernel.org,
        "Rafael J . Wysocki" <rafael@...nel.org>
Subject: Re: [PATCH][RFC v2] PCI: Workaround to enable poweroff on Mac Pro 11

On Fri, Aug 19, 2016 at 09:21:40AM +0200, Lukas Wunner wrote:
> On Fri, Aug 19, 2016 at 01:44:52AM +0800, Chen Yu wrote:
> > People reported that they can not do a poweroff nor a
> > suspend to memory on their Mac Pro 11. After some investigations
> > it was found that, once the PCI bridge 0000:00:1c.0 reassigns its
> > mm windows([mem 0x7fa00000-0x7fbfffff] and
> > [mem 0x7fc00000-0x7fdfffff 64bit pref]), the region of ACPI
> > io resource 0x1804 becomes unaccessible immediately, where the
> > ACPI Sleep register is located, as a result neither poweroff(S5)
> > nor suspend to memory(S3) works.
> > 
> > As suggested by Bjorn, further testing shows that, there is an
> > unreported device may be (using) conflict with above aperture,
> > so if we reassign the memory aperture to other place, the poweroff
> > works again.
> > 
> > As we did not find any resource declared in _CRS which contain above
> > memory aperture, thus we choose a simple workaround to clear the hotplug
> > flag(suggested by Yinghai Lu), thus do not allocate any resource for
> > this pci bridge.
> > 
> > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=103211
> > Cc: Bjorn Helgaas <bhelgaas@...gle.com>
> > Cc: Rafael J. Wysocki <rafael@...nel.org>
> > Signed-off-by: Chen Yu <yu.c.chen@...el.com>
> > ---
> >  drivers/pci/quirks.c | 21 +++++++++++++++++++++
> >  1 file changed, 21 insertions(+)
> > 
> > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> > index 37ff015..47b303a 100644
> > --- a/drivers/pci/quirks.c
> > +++ b/drivers/pci/quirks.c
> > @@ -2776,6 +2776,27 @@ static void quirk_hotplug_bridge(struct pci_dev *dev)
> >  DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_HINT, 0x0020, quirk_hotplug_bridge);
> >  
> >  /*
> > + * Apple: Avoid programming the memory/io aperture of 00:1c.0
> > + *
> > + * BIOS does not declare any resource for 00:1c.0, but with
> > + * hotplug flag set, thus OS allocate:
> > + * [mem 0x7fa00000 - 0x7fbfffff]
> > + * [mem 0x7fc00000-0x7fdfffff 64bit pref]
> > + * which is conflict with an unreported device, which
> > + * causes unpredictable result such as accessing io port.
> > + * So clear the hotplug flag to work around it.
> > + */
> > +static void quirk_apple_mbp_poweroff(struct pci_dev *dev)
> > +{
> > +	if (dmi_match(DMI_BOARD_VENDOR, "Apple Inc.") &&
> > +	    dmi_match(DMI_PRODUCT_NAME, "MacBookPro11,4") ||
> > +	    dmi_match(DMI_PRODUCT_NAME, "MacBookPro11,5"))
> 
> && has higher precedence than ||, so you would need parentheses here.
> However I don't think there's another vendor using those product names,
> so it's probably safe to drop the check for the vendor altogether.
>
You are right, will send another version. thanks!

Yu