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SubjectRe: [PATCH] PCI: Work around poweroff & suspend-to-RAM issue on Macbook Pro 11
Hi,
On Sun, Jul 02, 2017 at 03:59:48PM -0500, Bjorn Helgaas wrote:
> Neither soft poweroff (transition to ACPI power state S5) nor
> suspend-to-RAM (transition to state S3) works on the Macbook Pro 11,4 and
> 11,5.
>
> The problem is related to the [mem 0x7fa00000-0x7fbfffff] space. When we
> use that space, e.g., by assigning it to the 00:1c.0 Root Port, the ACPI
> Power Management 1 Control Register (PM1_CNT) at [io 0x1804] doesn't work
> anymore.
>
> Linux does a soft poweroff (transition to S5) by writing to PM1_CNT. The
> theory about why this doesn't work is:
>
> - The write to PM1_CNT causes an SMI
> - The BIOS SMI handler depends on something in
> [mem 0x7fa00000-0x7fbfffff]
> - When Linux assigns [mem 0x7fa00000-0x7fbfffff] to the 00:1c.0 Port, it
> covers up whatever the SMI handler uses, so the SMI handler no longer
> works correctly
>
> Reserve the [mem 0x7fa00000-0x7fbfffff] space so we don't assign it to
> anything.
>
> This is voodoo programming, since we don't know what the real conflict is,
> but we've failed to find the root cause.
>
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=103211
> Tested-by: thejoe@gmail.com
> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> Cc: stable@vger.kernel.org
> Cc: Rafael J. Wysocki <rafael@kernel.org>
> Cc: Lukas Wunner <lukas@wunner.de>
> Cc: Chen Yu <yu.c.chen@intel.com>
>
> diff --git a/arch/x86/pci/fixup.c b/arch/x86/pci/fixup.c
> index 6d52b94f4bb9..20fa7c84109d 100644
> --- a/arch/x86/pci/fixup.c
> +++ b/arch/x86/pci/fixup.c
> @@ -571,3 +571,35 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x2fc0, pci_invalid_bar);
> DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x6f60, pci_invalid_bar);
> DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x6fa0, pci_invalid_bar);
> DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x6fc0, pci_invalid_bar);
> +
> +/*
> + * Apple MacBook Pro: Avoid [mem 0x7fa00000-0x7fbfffff]
> + *
> + * Using the [mem 0x7fa00000-0x7fbfffff] region, e.g., by assigning it to
> + * the 00:1c.0 Root Port, causes a conflict with [io 0x1804], which is used
> + * for soft poweroff and suspend-to-RAM.
> + *
> + * As far as we know, this is related to the address space, not to the Root
> + * Port itself. Attaching the quirk to the Root Port is a convenience, but
> + * it could probably also be a standalone DMI quirk.
> + *
> + * https://bugzilla.kernel.org/show_bug.cgi?id=103211
> + */
> +static void quirk_apple_mbp_poweroff(struct pci_dev *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct resource *res;
> +
> + if ((!dmi_match(DMI_PRODUCT_NAME, "MacBookPro11,4") &&
> + !dmi_match(DMI_PRODUCT_NAME, "MacBookPro11,5")) ||
> + pdev->bus->number != 0 || pdev->devfn != PCI_DEVFN(0x1c, 0))
> + return;
> +
Not sure why we need to also the bus number of devfn, as there
is only one PCI bridge that would match 0x8c10? according to
https://bugzilla.kernel.org/attachment.cgi?id=210611
am I missing something?
thanks,
Yu
> + res = request_mem_region(0x7fa00000, 0x200000,
> + "MacBook Pro poweroff workaround");
> + if (res)
> + dev_info(dev, "claimed %s %pR\n", res->name, res);
> + else
> + dev_info(dev, "can't work around MacBook Pro poweroff issue\n");
> +}
> +DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x8c10, quirk_apple_mbp_poweroff);

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