ACPI: register ACPI Processor as generic thermal cooling device
Register ACPI processor as thermal cooling devices.
A combination of processor T-state and P-state are used for thermal throttling.
the processor will reduce the frequency first and then set the T-state.
we use cpufreq_thermal_reduction_pctg to calculate the cpufreq limit,
and call cpufreq_verify_with_limit to set the cpufreq limit.
if cpufreq driver is loaded, then we have four cooling state for cpufreq control.
cooling state 0: cpufreq limit == max_freq
cooling state 1: cpufreq limit == max_freq * 80%
cooling state 2: cpufreq limit == max_freq * 60%
cooling state 3: cpufreq limit == max_freq * 40%
after the cpufreq limit is set to 40 percentage of the max_freq,
we use T-state for cooling.
eg. a processor has P-state support, and it has 8 T-state (T0-T7),
the max_state of the proceesor is 10:
state cpufreq-limit T-state
0: max_freq T0
1: max_freq * 80% T0
2: max_freq * 60% T0
3: max_freq * 40% T0
4: max_freq * 40% T1
5: max_freq * 40% T2
6: max_freq * 40% T3
7: max_freq * 40% T4
8: max_freq * 40% T5
9: max_freq * 40% T6
10: max_freq * 40% T7
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Signed-off-by: Thomas Sujith <sujith.thomas@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
index e48ee4f..5668c5e 100644
--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -668,6 +668,24 @@
acpi_processor_power_init(pr, device);
+ pr->cdev = thermal_cooling_device_register("Processor", device,
+ &processor_cooling_ops);
+ if (pr->cdev)
+ printk(KERN_INFO PREFIX
+ "%s is registered as cooling_device%d\n",
+ device->dev.bus_id, pr->cdev->id);
+ else
+ goto end;
+
+ result = sysfs_create_link(&device->dev.kobj, &pr->cdev->device.kobj,
+ "thermal_cooling");
+ if (result)
+ return result;
+ result = sysfs_create_link(&pr->cdev->device.kobj, &device->dev.kobj,
+ "device");
+ if (result)
+ return result;
+
if (pr->flags.throttling) {
printk(KERN_INFO PREFIX "%s [%s] (supports",
acpi_device_name(device), acpi_device_bid(device));
@@ -791,6 +809,11 @@
acpi_processor_remove_fs(device);
+ sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
+ sysfs_remove_link(&pr->cdev->device.kobj, "device");
+ thermal_cooling_device_unregister(pr->cdev);
+ pr->cdev = NULL;
+
processors[pr->id] = NULL;
kfree(pr);
