linux-kernel - Re: [PATCH v1] ACPI: PM: s2idle: Evaluate all Low-Power S0 Idle

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Date: Tue, 23 Apr 2024 21:47:23 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Mario Limonciello <mario.limonciello@....com>
Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>, Linux ACPI <linux-acpi@...r.kernel.org>, 
	LKML <linux-kernel@...r.kernel.org>, Linux PM <linux-pm@...r.kernel.org>, 
	Mark Pearson <mpearson@...ovo.com>, "Rafael J. Wysocki" <rafael@...nel.org>
Subject: Re: [PATCH v1] ACPI: PM: s2idle: Evaluate all Low-Power S0 Idle _DSM functions

On Tue, Apr 23, 2024 at 9:40 PM Mario Limonciello
<mario.limonciello@....com> wrote:
>
> On 4/23/2024 14:19, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> >
> > Commit 073237281a50 ("ACPI: PM: s2idle: Enable Low-Power S0 Idle MSFT
> > UUID for non-AMD systems") attempted to avoid evaluating the same Low-
> > Power S0 Idle _DSM functions for different UUIDs, but that turns out to
> > be a mistake, because some systems in the field are adversely affected
> > by it.
> >
> > Address this by allowing  all Low-Power S0 Idle _DSM functions to be
> > evaluated, but still print the message regarding duplication of Low-
> > Power S0 Idle _DSM function sets for different UUIDs.
> >
> > Fixes: 073237281a50 ("ACPI: PM: s2idle: Enable Low-Power S0 Idle MSFT UUID for non-AMD systems")
> > Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218750
> > Reported-and-tested-by: Mark Pearson <mpearson@...ovo.com>
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>
> Ah glad to hear that my idea worked.

We've arrived at the same solution independently, I've only looked at
the BZ when the patch was ready to send.

> FWIW we saw the same type of issue
> on some AMD systems when we first introduced the MSFT UUID.
>
> Suggested-by: Mario Limonciello <mario.limonciello@....com>

But sure.

> Reviewed-by: Mario Limonciello <mario.limonciello@....com>

Thanks!

> > ---
> >   drivers/acpi/x86/s2idle.c |    8 +++-----
> >   1 file changed, 3 insertions(+), 5 deletions(-)
> >
> > Index: linux-pm/drivers/acpi/x86/s2idle.c
> > ===================================================================
> > --- linux-pm.orig/drivers/acpi/x86/s2idle.c
> > +++ linux-pm/drivers/acpi/x86/s2idle.c
> > @@ -492,16 +492,14 @@ static int lps0_device_attach(struct acp
> >                       unsigned int func_mask;
> >
> >                       /*
> > -                      * Avoid evaluating the same _DSM function for two
> > -                      * different UUIDs and prioritize the MSFT one.
> > +                      * Log a message if the _DSM function sets for two
> > +                      * different UUIDs overlap.
> >                        */
> >                       func_mask = lps0_dsm_func_mask & lps0_dsm_func_mask_microsoft;
> > -                     if (func_mask) {
> > +                     if (func_mask)
> >                               acpi_handle_info(adev->handle,
> >                                                "Duplicate LPS0 _DSM functions (mask: 0x%x)\n",
> >                                                func_mask);
> > -                             lps0_dsm_func_mask &= ~func_mask;
> > -                     }
> >               }
> >       }
> >
> >
> >
> >
>