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

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Date: Tue, 23 Apr 2024 21:19:36 +0200
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: 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>,
 Mario Limonciello <mario.limonciello@....com>
Subject:
 [PATCH v1] ACPI: PM: s2idle: Evaluate all Low-Power S0 Idle _DSM functions

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>
---
 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;
-			}
 		}
 	}