linux-kernel - Re: [PATCH 0/2] Stop using AMD GUID/

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Message-ID: <CAJZ5v0jNYs-X1tmhtJfbkKPga1AS9h-311LnxbEWHNrAT01utA@mail.gmail.com>
Date:   Thu, 22 Dec 2022 17:41:38 +0100
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Mario Limonciello <mario.limonciello@....com>
Cc:     rafael@...nel.org, Philipp Zabel <philipp.zabel@...il.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        anson.tsao@....com, ben@...eng.me, paul@...pog.com,
        bilkow@...anota.com, Shyam-sundar.S-k@....com,
        Len Brown <lenb@...nel.org>, linux-acpi@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/2] Stop using AMD GUID/_REV 2 by default

On Thu, Dec 15, 2022 at 8:16 PM Mario Limonciello
<mario.limonciello@....com> wrote:
>
> A number of laptops have been showing up where lots of EC controlled
> features weren't working after resume.  They've varied from KBD
> backlight, to fans, brightness control and lots more.
> In kernel 6.1 we introduced a module parameter through
> commit a0bc002393d4 ("ACPI: x86: s2idle: Add module parameter to
> prefer Microsoft GUID") and a series of quirks in follow up commits
> for systems that people reported the problems.
>
> 3 more systems recently reported issues; and so rather than increasing
> the list /again/ to add these new systems we took a hard look at the
> "why".
>
> The AMD GUID/_REV 2 path was introduced for vendors to be able to
> differentiate from the Microsoft path.  Vendors could populate this
> with unique code for their designs.  Conceptually this was supposed
> to help the ecosystem, however in practice we've found that there
> are more machines that don't populate it than do.
>
> The only models that have populated this with unique code for avoiding
> a bug specific to their design is the HP Elitebook 835, 845, and 865 G9
> systems.
>
> To avoid growing the list further this series rips out the module
> parameter support, all the quirks and sets the default policy to follow
> the Microsoft GUID path for AMD Rembrandt or later.  We validated this
> on OEM systems and we found this fixes them.
>
> To avoid regressing the HP systems that use the AMD GUID/_REV 2
> path, let them keep taking it. The reason they take it is believed to
> be a bug with WLAN firmware.  If this is fixed in the future, we may
> consider dropping the HP systems as well and having no quirks.
>
> Mario Limonciello (2):
>   ACPI: x86: s2idle: Force AMD GUID/_REV 2 on HP Elitebook 865
>   ACPI: x86: s2idle: Stop using AMD specific codepath for Rembrandt+
>
>  drivers/acpi/x86/s2idle.c | 87 ++++++---------------------------------
>  1 file changed, 13 insertions(+), 74 deletions(-)
>
> --

Both patches applied as 6.2-rc material, thanks!