RE: acpi PNP0C14:02: duplicate WMI GUID 05901221-D566-11D1-B2F0-00A0C9062910

[Limonciello, Mario]

> -----Original Message-----
> From: Christian Kujau <lists@xxxxxxxxxxxxxxx>
> Sent: Tuesday, November 3, 2020 17:41
> To: Limonciello, Mario; Andy Lutomirski; platform-driver-x86@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Subject: acpi PNP0C14:02: duplicate WMI GUID 05901221-D566-11D1-B2F0-
> 00A0C9062910
> 
> 
> [EXTERNAL EMAIL]
> 
> Hi,
> 
> while looking through boot messages I came across the following on a
> Lenovo T470 laptop with Linux 5.8:
> 
>   acpi PNP0C14:02: duplicate WMI GUID 05901221-D566-11D1-B2F0-00A0C9062910
> (first instance was on PNP0C14:01)
>   acpi PNP0C14:03: duplicate WMI GUID 05901221-D566-11D1-B2F0-00A0C9062910
> (first instance was on PNP0C14:01)
> 
> Searching the interwebs brought me to an old patch proposal:
> 
>  > https://lkml.org/lkml/2017/12/8/914
>  > Fri, 8 Dec 2017 20:34:21 -0600
>  > [PATCH 2/2] platform/x86: wmi: Allow creating WMI devices with the same
> GUID
> 
> The patch was proposed, but never made it into mainline. It's not really a
> big deal, booting continues and all devices appear to work, only these two
> messages get logged during boot. I'm just wondering if this needs to be
> fixed or if it's really just a cosmetic issue.
> 
> Full dmesg: https://pastebin.ubuntu.com/p/2pPv3hywPF/
> 

The message is correct.  An assumption has been made that two devices can't
provide the same GUID in the kernel early on, but this is an incorrect assumption.

We haven't had a situation that we actually need to bind to devices that both provide
the same GUID so this has never been a priority to solve.