linux-kernel - [PATCH] intel: thermal: PCH: Drop ACPI_FADT_LOW_POWER

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Date:   Thu, 14 Jul 2022 21:11:26 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Linux PM <linux-pm@...r.kernel.org>
Cc:     Linux ACPI <linux-acpi@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Zhang Rui <rui.zhang@...el.com>,
        Mario Limonciello <mario.limonciello@....com>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Subject: [PATCH] intel: thermal: PCH: Drop ACPI_FADT_LOW_POWER_S0 check

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

If ACPI_FADT_LOW_POWER_S0 is not set, this doesn't mean that low-power
S0 idle is not usable.  It merely means that using S3 on the given
system is more beneficial from the energy saving perspective than using
low-power S0 idle, as long as S3 is supported.

Suspend-to-idle is still a valid suspend mode if ACPI_FADT_LOW_POWER_S0
is not set and the pm_suspend_via_firmware() check in pch_wpt_suspend()
is sufficient to distinguish suspend-to-idle from S3, so drop the
confusing ACPI_FADT_LOW_POWER_S0 check.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/thermal/intel/intel_pch_thermal.c |    8 --------
 1 file changed, 8 deletions(-)

Index: linux-pm/drivers/thermal/intel/intel_pch_thermal.c
===================================================================
--- linux-pm.orig/drivers/thermal/intel/intel_pch_thermal.c
+++ linux-pm/drivers/thermal/intel/intel_pch_thermal.c
@@ -207,14 +207,6 @@ static int pch_wpt_suspend(struct pch_th
 		return 0;
 	}

-	/* Do not check temperature if it is not a S0ix capable platform */
-#ifdef CONFIG_ACPI
-	if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0))
-		return 0;
-#else
-	return 0;
-#endif
-
 	/* Do not check temperature if it is not s2idle */
 	if (pm_suspend_via_firmware())
 		return 0;