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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Mon, 18 Nov 2019 10:03:27 +0100
Message-ID: <CAJZ5v0g35zvSB88d7qK8n1uRGCuO5VNK11jHVQRNKwyQW4vZSQ@mail.gmail.com>
Subject: Re: [PATCH v2] ACPI: sysfs: Change ACPI_MASKABLE_GPE_MAX to 0x100
To:     Dan Williams <dan.j.williams@intel.com>
Cc:     Yunfeng Ye <yeyunfeng@huawei.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Len Brown <lenb@kernel.org>,
        Linux ACPI <linux-acpi@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        "hushiyuan@huawei.com" <hushiyuan@huawei.com>,
        "linfeilong@huawei.com" <linfeilong@huawei.com>
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On Sat, Nov 16, 2019 at 9:06 PM Dan Williams <dan.j.williams@intel.com> wrote:
>
> On Wed, Nov 13, 2019 at 11:17 PM Yunfeng Ye <yeyunfeng@huawei.com> wrote:
> >
> > The commit 0f27cff8597d ("ACPI: sysfs: Make ACPI GPE mask kernel
> > parameter cover all GPEs") says:
> >   "Use a bitmap of size 0xFF instead of a u64 for the GPE mask so 256
> >    GPEs can be masked"
> >
> > But the masking of GPE 0xFF it not supported and the check condition
> > "gpe > ACPI_MASKABLE_GPE_MAX" is not valid because the type of gpe is
> > u8.
> >
> > So modify the macro ACPI_MASKABLE_GPE_MAX to 0x100, and drop the "gpe >
> > ACPI_MASKABLE_GPE_MAX" check. In addition, update the docs "Format" for
> > acpi_mask_gpe parameter.
> >
> > Fixes: 0f27cff8597d ("ACPI: sysfs: Make ACPI GPE mask kernel parameter cover all GPEs")
> > Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com>
> > ---
> > v1 -> v2:
> >  - drop the "gpe > ACPI_MASKABLE_GPE_MAX" check
> >  - update the docs "Format" from <int> to <byte> for acpi_mask_gpe parameter
> >  - update the commit comment
> >
> >  Documentation/admin-guide/kernel-parameters.txt | 2 +-
> >  drivers/acpi/sysfs.c                            | 4 ++--
> >  2 files changed, 3 insertions(+), 3 deletions(-)
>
> Bisect flags commit eb09878e1301 "ACPI: sysfs: Change
> ACPI_MASKABLE_GPE_MAX to 0x100" in -next as the reason for a boot
> regression in my qemu-kvm test environment. It spews:
>
> [    1.456728] ACPI: Masking GPE 0x0.
> ...
> [  161.721420] ACPI: Masking GPE 0x0.
>
> ...and then hangs.
>
> A straight revert gets the configuration back on its feet.
>
> qemu-system-x86_64 --version
> QEMU emulator version 4.0.50 (v4.0.0-928-g49c6c6ac0cd8)

OK, I'll drop it then, thanks!