[PATCH 1/2] ACPI: Evaluate thermal trip points before reading temperature

[PATCH 1/2] ACPI: Evaluate thermal trip points before reading temperature

[Matthew Garrett]

An HP laptop (Pavilion G4-1016tx) has the following code in _TMP:

       Store (\_SB.PCI0.LPCB.EC0.RTMP, Local0)
       If (LGreaterEqual (Local0, S4TP))
       {
           Store (One, HTS4)
       }

S4TP is initialised at 0 and not programmed further until either _HOT or
_CRT is called. If we evaluate _TMP before the trip points then HTS4 will
always be set, causing the firmware to generate a message on boot
complaining that the system shut down because of overheating. The simplest
solution is just to reverse the checking of trip points and _TMP in thermal
init.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
---
 drivers/acpi/thermal.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
index 48fbc64..7dbebea 100644
--- a/drivers/acpi/thermal.c
+++ b/drivers/acpi/thermal.c
@@ -941,13 +941,13 @@ static int acpi_thermal_get_info(struct acpi_thermal *tz)
 	if (!tz)
 		return -EINVAL;
 
-	/* Get temperature [_TMP] (required) */
-	result = acpi_thermal_get_temperature(tz);
+	/* Get trip points [_CRT, _PSV, etc.] (required) */
+	result = acpi_thermal_get_trip_points(tz);
 	if (result)
 		return result;
 
-	/* Get trip points [_CRT, _PSV, etc.] (required) */
-	result = acpi_thermal_get_trip_points(tz);
+	/* Get temperature [_TMP] (required) */
+	result = acpi_thermal_get_temperature(tz);
 	if (result)
 		return result;
 
-- 
1.7.7.1

[PATCH 2/2] ACPI: Ensure thermal limits match CPU frequencies

[Matthew Garrett]

The ACPI thermal management code supports slowing down a CPU when it's
overheating. Right now that's done by choosing to run it at 100%, 75%, 50%
or 25% of full speed. However, most CPUs do not allow an arbitrary
frequency to be set and so will run at the first frequency below that value.
This doesn't match the intent of the specification, which is to drop the
frequency state by state until the temperature stabalises. Fix this up
so it uses actual frequencies rather than percentages.

Reported by: Gene Snider <snider6982@comcast.net>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
---
 drivers/acpi/processor_thermal.c |   45 +++++++++++++++++++++----------------
 1 files changed, 25 insertions(+), 20 deletions(-)

diff --git a/drivers/acpi/processor_thermal.c b/drivers/acpi/processor_thermal.c
index 3b599ab..1fbf539 100644
--- a/drivers/acpi/processor_thermal.c
+++ b/drivers/acpi/processor_thermal.c
@@ -51,10 +51,8 @@ ACPI_MODULE_NAME("processor_thermal");
  * _any_ cpufreq driver and not only the acpi-cpufreq driver.
  */
 
-#define CPUFREQ_THERMAL_MIN_STEP 0
-#define CPUFREQ_THERMAL_MAX_STEP 3
 
-static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg);
+static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_limit_state);
 static unsigned int acpi_thermal_cpufreq_is_init = 0;
 
 static int cpu_has_cpufreq(unsigned int cpu)
@@ -69,19 +67,19 @@ static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb,
 					 unsigned long event, void *data)
 {
 	struct cpufreq_policy *policy = data;
-	unsigned long max_freq = 0;
+	int state = per_cpu(cpufreq_thermal_limit_state, policy->cpu);
+	struct cpufreq_frequency_table *table;
 
 	if (event != CPUFREQ_ADJUST)
-		goto out;
+		return 0;
+
+	table = cpufreq_frequency_get_table(policy->cpu);
 
-	max_freq = (
-	    policy->cpuinfo.max_freq *
-	    (100 - per_cpu(cpufreq_thermal_reduction_pctg, policy->cpu) * 20)
-	) / 100;
+	if (!table)
+		return 0;
 
-	cpufreq_verify_within_limits(policy, 0, max_freq);
+	cpufreq_verify_within_limits(policy, 0, table[state].frequency);
 
-      out:
 	return 0;
 }
 
@@ -91,10 +89,21 @@ static struct notifier_block acpi_thermal_cpufreq_notifier_block = {
 
 static int cpufreq_get_max_state(unsigned int cpu)
 {
+	int count = 0;
+	struct cpufreq_frequency_table *table;
+
 	if (!cpu_has_cpufreq(cpu))
 		return 0;
 
-	return CPUFREQ_THERMAL_MAX_STEP;
+	table = cpufreq_frequency_get_table(cpu);
+
+	if (!table)
+		return 0;
+
+	while (table[count].frequency != CPUFREQ_TABLE_END)
+		count++;
+
+	return count;
 }
 
 static int cpufreq_get_cur_state(unsigned int cpu)
@@ -102,7 +111,7 @@ static int cpufreq_get_cur_state(unsigned int cpu)
 	if (!cpu_has_cpufreq(cpu))
 		return 0;
 
-	return per_cpu(cpufreq_thermal_reduction_pctg, cpu);
+	return per_cpu(cpufreq_thermal_limit_state, cpu);
 }
 
 static int cpufreq_set_cur_state(unsigned int cpu, int state)
@@ -110,7 +119,7 @@ static int cpufreq_set_cur_state(unsigned int cpu, int state)
 	if (!cpu_has_cpufreq(cpu))
 		return 0;
 
-	per_cpu(cpufreq_thermal_reduction_pctg, cpu) = state;
+	per_cpu(cpufreq_thermal_limit_state, cpu) = state;
 	cpufreq_update_policy(cpu);
 	return 0;
 }
@@ -121,7 +130,7 @@ void acpi_thermal_cpufreq_init(void)
 
 	for (i = 0; i < nr_cpu_ids; i++)
 		if (cpu_present(i))
-			per_cpu(cpufreq_thermal_reduction_pctg, i) = 0;
+			per_cpu(cpufreq_thermal_limit_state, i) = 0;
 
 	i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block,
 				      CPUFREQ_POLICY_NOTIFIER);
@@ -169,15 +178,11 @@ int acpi_processor_get_limit_info(struct acpi_processor *pr)
 	return 0;
 }
 
-/* thermal coolign device callbacks */
+/* thermal cooling device callbacks */
 static int acpi_processor_max_state(struct acpi_processor *pr)
 {
 	int max_state = 0;
 
-	/*
-	 * There exists four states according to
-	 * cpufreq_thermal_reduction_ptg. 0, 1, 2, 3
-	 */
 	max_state += cpufreq_get_max_state(pr->id);
 	if (pr->flags.throttling)
 		max_state += (pr->throttling.state_count -1);
-- 
1.7.7.1