[G/Unstable/OEM-5.10] [PATCH 6/7] thermal: int340x: Fix unexpected shutdown at critical temperature

[Kai-Heng Feng]

BugLink: https://bugs.launchpad.net/bugs/1906168

We are seeing thermal shutdown on Intel based mobile workstations, the
shutdown happens during the first trip handle in
thermal_zone_device_register():
kernel: thermal thermal_zone15: critical temperature reached (101 C), shutting down

However, we shouldn't do a thermal shutdown here, since
1) We may want to use a dedicated daemon, Intel's thermald in this case,
to handle thermal shutdown.

2) For ACPI based system, _CRT doesn't mean shutdown unless it's inside
ThermalZone namespace. ACPI Spec, 11.4.4 _CRT (Critical Temperature):
"... If this object it present under a device, the device’s driver
evaluates this object to determine the device’s critical cooling
temperature trip point. This value may then be used by the device’s
driver to program an internal device temperature sensor trip point."

So a "critical trip" here merely means we should take a more aggressive
cooling method.

As int340x device isn't present under ACPI ThermalZone, override the
default .critical callback to prevent surprising thermal shutdown.

Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano at linaro.org>
Link: https://lore.kernel.org/r/20201221172345.36976-1-kai.heng.feng@canonical.com
(cherry picked from commit dd47366aaa9b93ac3d97cb4ee7641d38a28a771e linux-next)
Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
---
 .../thermal/intel/int340x_thermal/int340x_thermal_zone.c    | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/thermal/intel/int340x_thermal/int340x_thermal_zone.c b/drivers/thermal/intel/int340x_thermal/int340x_thermal_zone.c
index 432213272f1e..eeb08fab19a7 100644
--- a/drivers/thermal/intel/int340x_thermal/int340x_thermal_zone.c
+++ b/drivers/thermal/intel/int340x_thermal/int340x_thermal_zone.c
@@ -146,12 +146,18 @@ static int int340x_thermal_get_trip_hyst(struct thermal_zone_device *zone,
 	return 0;
 }
 
+static void int340x_thermal_critical(struct thermal_zone_device *zone)
+{
+	dev_dbg(&zone->device, "%s: critical temperature reached\n", zone->type);
+}
+
 static struct thermal_zone_device_ops int340x_thermal_zone_ops = {
 	.get_temp       = int340x_thermal_get_zone_temp,
 	.get_trip_temp	= int340x_thermal_get_trip_temp,
 	.get_trip_type	= int340x_thermal_get_trip_type,
 	.set_trip_temp	= int340x_thermal_set_trip_temp,
 	.get_trip_hyst =  int340x_thermal_get_trip_hyst,
+	.critical	= int340x_thermal_critical,
 };
 
 static int int340x_thermal_get_trip_config(acpi_handle handle, char *name,
-- 
2.29.2