2024-06-05 20:15:43

by Rafael J. Wysocki

[permalink] [raw]
Subject: [PATCH v1] thermal: ACPI: Invalidate trip points with temperature of 0 or below

From: Rafael J. Wysocki <[email protected]>

It is reported that commit 950210887670 ("thermal: core: Drop
trips_disabled bitmask") causes the maximum frequency of CPUs to drop
further down with every system sleep-wake cycle on Intel Core i7-4710HQ.

This turns out to be due to a trip point whose temperature is equal to 0
degrees Celsius which is acted on every time the system wakes from sleep.

Before commit 950210887670 this trip point would be disabled wia the
trips_disabled bitmask, but now it is treated as a valid one.

Since ACPI thermal control is generally about protection against
overheating, trip points with temperature of 0 centigrade or below are
not particularly useful there, so initialize them all as invalid which
fixes the problem at hand.

Fixes: 950210887670 ("thermal: core: Drop trips_disabled bitmask")
Closes: https://lore.kernel.org/linux-pm/[email protected]
Reported-by: Tibor Billes <[email protected]>
Tested-by: Tibor Billes <[email protected]>
Cc: 6.7+ <[email protected]> # 6.7+
Signed-off-by: Rafael J. Wysocki <[email protected]>
---
drivers/acpi/thermal.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

Index: linux-pm/drivers/acpi/thermal.c
===================================================================
--- linux-pm.orig/drivers/acpi/thermal.c
+++ linux-pm/drivers/acpi/thermal.c
@@ -168,11 +168,17 @@ static int acpi_thermal_get_polling_freq

static int acpi_thermal_temp(struct acpi_thermal *tz, int temp_deci_k)
{
+ int temp;
+
if (temp_deci_k == THERMAL_TEMP_INVALID)
return THERMAL_TEMP_INVALID;

- return deci_kelvin_to_millicelsius_with_offset(temp_deci_k,
+ temp = deci_kelvin_to_millicelsius_with_offset(temp_deci_k,
tz->kelvin_offset);
+ if (temp <= 0)
+ return THERMAL_TEMP_INVALID;
+
+ return temp;
}

static bool acpi_thermal_trip_valid(struct acpi_thermal_trip *acpi_trip)