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

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Date: Tue, 23 Apr 2024 14:40:41 -0500
From: Mario Limonciello <mario.limonciello@....com>
To: "Rafael J. Wysocki" <rjw@...ysocki.net>,
 Linux ACPI <linux-acpi@...r.kernel.org>
Cc: 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 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.  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>
Reviewed-by: Mario Limonciello <mario.limonciello@....com>

> ---
>   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;
> -			}
>   		}
>   	}
>   
> 
> 
>