Message-ID: <0113ca60-acf2-f4db-3230-959e9bb15726@o2.pl>
Date:   Mon, 23 Jan 2023 22:00:43 +0100
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Subject: Re: [PATCH v3 RESEND] acpi,pci: warn about duplicate IRQ routing
 entries returned from _PRT
Content-Language: en-GB
To:     Bjorn Helgaas <helgaas@kernel.org>
Cc:     linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
        linux-acpi@vger.kernel.org, linux-i2c@vger.kernel.org,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Len Brown <lenb@kernel.org>, Borislav Petkov <bp@suse.de>,
        Jean Delvare <jdelvare@suse.com>,
        Jean Delvare <jdelvare@suse.de>
References: <20230123203301.GA909338@bhelgaas>
From:   =?UTF-8?Q?Mateusz_Jo=c5=84czyk?= <mat.jonczyk@o2.pl>
In-Reply-To: <20230123203301.GA909338@bhelgaas>
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W dniu 23.01.2023 o 21:33, Bjorn Helgaas pisze:
> On Sat, Jan 21, 2023 at 04:33:14PM +0100, Mateusz Jończyk wrote:
>> On some platforms, the ACPI _PRT function returns duplicate interrupt
>> routing entries. Linux uses the first matching entry, but sometimes the
>> second matching entry contains the correct interrupt vector.
>>
>> Print an error to dmesg if duplicate interrupt routing entries are
>> present, so that we could check how many models are affected.
> It shouldn't be too hard to use qemu to figure out whether Windows
> uses the last matching entry, i.e., treating _PRT entries as
> assignments.  If so, maybe Linux could just do the same.
>
> Is anybody up for that?
>
> Bjorn

The hardware in question has a working Windows XP installation,
and I could in theory check which interrupt vector it uses - but
I think that such reverse engineering is forbidden by Windows' EULA.

Greetings,
Mateusz