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From:   Dexuan-Linux Cui <dexuan.linux@gmail.com>
Date:   Mon, 18 Nov 2019 11:44:22 -0800
Message-ID: <CAA42JLYCod=mymBiDDXxQ1sts7e-Ot_q9SKdJxjSkcsZRVGDTQ@mail.gmail.com>
Subject: Re: [PATCH v2] ACPI: sysfs: Change ACPI_MASKABLE_GPE_MAX to 0x100
To:     "Rafael J. Wysocki" <rafael@kernel.org>
Cc:     Dan Williams <dan.j.williams@intel.com>,
        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>,
        Dexuan Cui <decui@microsoft.com>
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On Mon, Nov 18, 2019 at 1:04 AM Rafael J. Wysocki <rafael@kernel.org> wrote:
>
> 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!

We're seeing the same issue wtih 5.4.0-rc7-next-20191118 on a Linux VM
running on Hyper-V :

[    0.133029] ACPI: 1 ACPI AML tables successfully acquired and loaded
[    0.144023] ACPI: Interpreter enabled
[    0.145023] ACPI: (supports S0 S5)
[    0.146023] ACPI: Using IOAPIC for interrupt routing
[    0.147024] PCI: Using host bridge windows from ACPI; if necessary,
use "pci=nocrs" and report a bug
[    0.148031] ACPI: Masking GPE 0x0.
...
[  774.839023] ACPI: Masking GPE 0x0.
[  774.840023] ACPI: Masking GPE 0x0.

I guess the patch is only tested on a physical machine and not on a VM...

Thanks,
Dexuan