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

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Message-ID: <20160819072140.GA10854@wunner.de>
Date:   Fri, 19 Aug 2016 09:21:40 +0200
From:   Lukas Wunner <lukas@...ner.de>
To:     Chen Yu <yu.c.chen@...el.com>
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 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.

Best regards,

Lukas

> +		dev->is_hotplug_bridge = 0;
> +}
> +
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x8c10, quirk_apple_mbp_poweroff);
> +
> +/*
>   * This is a quirk for the Ricoh MMC controller found as a part of
>   * some mulifunction chips.
>  
> -- 
> 2.7.4