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From:   Vitaly Kuznetsov <vkuznets@redhat.com>
To:     Bjorn Helgaas <helgaas@kernel.org>, Rob Herring <robh@kernel.org>
Cc:     Donald Hunter <donald.hunter@gmail.com>,
        Binbin Zhou <zhoubinbin@loongson.cn>,
        Liu Peibao <liupeibao@loongson.cn>,
        Huacai Chen <chenhuacai@loongson.cn>,
        Jesse Brandeburg <jesse.brandeburg@intel.com>,
        Tony Nguyen <anthony.l.nguyen@intel.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
        regressions@lists.linux.dev, mstowe@redhat.com
Subject: Re: [PATCH] PCI: Restrict device disabled status check to DT
In-Reply-To: <20230419202042.GA223738@bhelgaas>
References: <20230419202042.GA223738@bhelgaas>
Date:   Thu, 20 Apr 2023 11:30:04 +0200
Message-ID: <87leimnboj.fsf@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

Bjorn Helgaas <helgaas@kernel.org> writes:

> [+cc Vitaly, Jesse, Tony, Andy, regressions, regarding reports of
> hang or crash during boot in igb driver, some with AWS Xen]
>
> On Wed, Apr 19, 2023 at 02:35:13PM -0500, Rob Herring wrote:
>> Commit 6fffbc7ae137 ("PCI: Honor firmware's device disabled status")
>> checked the firmware device status for both DT and ACPI devices. That
>> caused a regression in some ACPI systems. The exact reason isn't clear.
>> It's possibly a firmware bug. For now, at least, refactor the check to
>> be for DT based systems only.
>> 
>> Note that the original implementation leaked a refcount which is now
>> correctly handled.
>> 
>> Fixes: 6fffbc7ae137 ("PCI: Honor firmware's device disabled status")
>> Link: https://lore.kernel.org/all/m2fs9lgndw.fsf@gmail.com/
>> Reported-by: Donald Hunter <donald.hunter@gmail.com>
>> Cc: Binbin Zhou <zhoubinbin@loongson.cn>
>> Cc: Liu Peibao <liupeibao@loongson.cn>
>> Cc: Huacai Chen <chenhuacai@loongson.cn>
>> Signed-off-by: Rob Herring <robh@kernel.org>
>
> Applied to for-linus for (hopefully) v6.3.  I added:
>
>   [bhelgaas: Per ACPI r6.5, sec 6.3.7, for devices on an enumerable
>   bus, _STA must return with bit[0] ("device is present") set]
>
>   Link: https://bugzilla.kernel.org/show_bug.cgi?id=217317
>
> It would be really great if anybody who has seen this issue could test
> and report whether this patch solves it.
>

[Cc: Myron]

I can confirm the patch fixes the issue I've reported with AWS Xen
instances, so:

Tested-by:  Vitaly Kuznetsov <vkuznets@redhat.com>

-- 
Vitaly