Re: FW: ACPI too sensitive about critical temperature

[Pavel Machek <pavel-+ZI9xUNit7I@public.gmane.org>]

Hi!

> I didn't want to bug the whole lkml with this, so I'm sending this to 
> you guys who wrote "drivers/acpi/thermal.c". I hope that's okay...
> 
> A friend of mine has a mainboard (I can find out the specific type if 
> you want to know) which reports inaccurately high temperature "peaks" 
> from time to time.
> Looking at /proc/acpi/thermal_zone/THR1/temperature every second might 
> look something like this: 45, 43, 47, 42, 90, 43, 41, 45

Try this one.

								Pavel

--- clean/drivers/acpi/thermal.c	2003-07-27 22:31:09.000000000 +0200
+++ linux/drivers/acpi/thermal.c	2004-01-13 22:33:49.000000000 +0100
@@ -223,8 +223,11 @@
 	tz->last_temperature = tz->temperature;
 
 	status = acpi_evaluate_integer(tz->handle, "_TMP", NULL, &tz->temperature);
-	if (ACPI_FAILURE(status))
+	if (ACPI_FAILURE(status)) {
+		if (tz->temperature != tz->last_temperature)
+			printk(KERN_ERR "temperature damaged while processing\n");
 		return -ENODEV;
+	}
 
 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Temperature is %lu dK\n", tz->temperature));
 
@@ -457,7 +460,17 @@
 		return_VALUE(-EINVAL);
 
 	if (tz->temperature >= tz->trips.critical.temperature) {
+		long old_temperature = tz->temperature;
 		ACPI_DEBUG_PRINT((ACPI_DB_WARN, "Critical trip point\n"));
+
+		result = acpi_thermal_get_temperature(tz);
+		if (!result) {
+			if (tz->temperature < (tz->trips.critical.temperature - 100)) {
+				printk(KERN_ALERT "ACPI changed its mind about temperature, was %ld C, now %ld C", 
+				       KELVIN_TO_CELSIUS(old_temperature), KELVIN_TO_CELSIUS(tz->temperature));
+				return_VALUE(0);
+			}
+		}
 		tz->trips.critical.flags.enabled = 1;
 	}
 	else if (tz->trips.critical.flags.enabled)
@@ -467,8 +480,8 @@
 	if (result)
 		return_VALUE(result);
 
+	printk(KERN_EMERG "Critical temperature reached (%ld C), shutting down.\n", KELVIN_TO_CELSIUS(tz->temperature));
 	acpi_bus_generate_event(device, ACPI_THERMAL_NOTIFY_CRITICAL, tz->trips.critical.flags.enabled);
-
 	acpi_thermal_call_usermode(ACPI_THERMAL_PATH_POWEROFF);
 
 	return_VALUE(0);

-- 
When do you have a heart between your knees?
[Johanka's followup: and *two* hearts?]


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