platform/x86: acer-wmi: Fix initialization of last_non_turbo_profile

JIRA: https://issues.redhat.com/browse/RHEL-89362

commit 3ef4ea5
Author: Armin Wolf <W_Armin@gmx.de>
Date:   Sun Jan 19 21:17:23 2025 +0100

On machines that do not support the balanced profile the value of
last_non_turbo_profile is invalid after initialization which might
cause the driver to switch to an unsupported platform profile later.

Fix this by only setting last_non_turbo_profile to supported platform
profile values.

Fixes: 191e21f ("platform/x86: acer-wmi: use an ACPI bitmap to set the platform profile choices")
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Tested-by: Hridesh MG <hridesh699@gmail.com>
Reviewed-by: Hridesh MG <hridesh699@gmail.com>
Link: https://lore.kernel.org/r/20250119201723.11102-3-W_Armin@gmx.de
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Mark Langsdorf <mlangsdo@redhat.com>

Author: mlangsdorf

drivers/platform/x86/acer-wmi.c

@@ -755,7 +755,7 @@ static bool platform_profile_support;
  * The profile used before turbo mode. This variable is needed for
  * returning from turbo mode when the mode key is in toggle mode.
  */
-static int last_non_turbo_profile;
+static int last_non_turbo_profile = INT_MIN;
 
 /* The most performant supported profile */
 static int acer_predator_v4_max_perf;
@@ -1997,32 +1997,43 @@ acer_predator_v4_platform_profile_probe(void *drvdata, unsigned long *choices)
 	/* Iterate through supported profiles in order of increasing performance */
 	if (test_bit(ACER_PREDATOR_V4_THERMAL_PROFILE_ECO, &supported_profiles)) {
 		set_bit(PLATFORM_PROFILE_LOW_POWER, choices);
-		acer_predator_v4_max_perf =
-			ACER_PREDATOR_V4_THERMAL_PROFILE_ECO;
+		acer_predator_v4_max_perf = ACER_PREDATOR_V4_THERMAL_PROFILE_ECO;
+		last_non_turbo_profile = ACER_PREDATOR_V4_THERMAL_PROFILE_ECO;
 	}
 
 	if (test_bit(ACER_PREDATOR_V4_THERMAL_PROFILE_QUIET, &supported_profiles)) {
 		set_bit(PLATFORM_PROFILE_QUIET, choices);
-		acer_predator_v4_max_perf =
-			ACER_PREDATOR_V4_THERMAL_PROFILE_QUIET;
+		acer_predator_v4_max_perf = ACER_PREDATOR_V4_THERMAL_PROFILE_QUIET;
+		last_non_turbo_profile = ACER_PREDATOR_V4_THERMAL_PROFILE_QUIET;
 	}
 
 	if (test_bit(ACER_PREDATOR_V4_THERMAL_PROFILE_BALANCED, &supported_profiles)) {
 		set_bit(PLATFORM_PROFILE_BALANCED, choices);
-		acer_predator_v4_max_perf =
-			ACER_PREDATOR_V4_THERMAL_PROFILE_BALANCED;
+		acer_predator_v4_max_perf = ACER_PREDATOR_V4_THERMAL_PROFILE_BALANCED;
+		last_non_turbo_profile = ACER_PREDATOR_V4_THERMAL_PROFILE_BALANCED;
 	}
 
 	if (test_bit(ACER_PREDATOR_V4_THERMAL_PROFILE_PERFORMANCE, &supported_profiles)) {
 		set_bit(PLATFORM_PROFILE_BALANCED_PERFORMANCE, choices);
-		acer_predator_v4_max_perf =
-			ACER_PREDATOR_V4_THERMAL_PROFILE_PERFORMANCE;
+		acer_predator_v4_max_perf = ACER_PREDATOR_V4_THERMAL_PROFILE_PERFORMANCE;
+
+		/* We only use this profile as a fallback option in case no prior
+		 * profile is supported.
+		 */
+		if (last_non_turbo_profile < 0)
+			last_non_turbo_profile = ACER_PREDATOR_V4_THERMAL_PROFILE_PERFORMANCE;
 	}
 
 	if (test_bit(ACER_PREDATOR_V4_THERMAL_PROFILE_TURBO, &supported_profiles)) {
 		set_bit(PLATFORM_PROFILE_PERFORMANCE, choices);
-		acer_predator_v4_max_perf =
-			ACER_PREDATOR_V4_THERMAL_PROFILE_TURBO;
+		acer_predator_v4_max_perf = ACER_PREDATOR_V4_THERMAL_PROFILE_TURBO;
+
+		/* We need to handle the hypothetical case where only the turbo profile
+		 * is supported. In this case the turbo toggle will essentially be a
+		 * no-op.
+		 */
+		if (last_non_turbo_profile < 0)
+			last_non_turbo_profile = ACER_PREDATOR_V4_THERMAL_PROFILE_TURBO;
 	}
 
 	return 0;
@@ -2043,10 +2054,6 @@ static int acer_platform_profile_setup(struct platform_device *device)
 			return PTR_ERR(platform_profile_device);
 
 		platform_profile_support = true;
-
-		/* Set default non-turbo profile  */
-		last_non_turbo_profile =
-			ACER_PREDATOR_V4_THERMAL_PROFILE_BALANCED;
 	}
 	return 0;
 }
@@ -2064,6 +2071,10 @@ static int acer_thermal_profile_change(void)
 		if (cycle_gaming_thermal_profile) {
 			platform_profile_cycle();
 		} else {
+			/* Do nothing if no suitable platform profiles where found */
+			if (last_non_turbo_profile < 0)
+				return 0;
+
 			err = WMID_gaming_get_misc_setting(
 				ACER_WMID_MISC_SETTING_PLATFORM_PROFILE, &current_tp);
 			if (err)