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Diffstat (limited to 'Documentation/drivers/dptf.md')
| -rw-r--r-- | Documentation/drivers/dptf.md | 28 |
1 files changed, 14 insertions, 14 deletions
diff --git a/Documentation/drivers/dptf.md b/Documentation/drivers/dptf.md index 1e5674c9d9..75c713e15c 100644 --- a/Documentation/drivers/dptf.md +++ b/Documentation/drivers/dptf.md @@ -43,7 +43,7 @@ This policy monitors the temperature of participants and controls fans to spin at varying speeds. These speeds are defined by the platform, and will be enabled depending on the various temperatures reported by participants. -# Note about units +## Note about units ACPI uses unusual units for specifying various physical measurements. For example, temperatures are specified in 10ths of a degree K, and time is measured @@ -69,7 +69,7 @@ data was a 0). The following Methods were removed: 2) There is no more implicit inclusion of _ACn methods for TCPU (these must be specified in the devicetree entries or by calling the DPTF acpigen API). -# ACPI Tables +## ACPI Tables DPTF relies on an assortment of ACPI tables to provide parameters to the DPTF application. We will discuss the more important ones here. @@ -108,7 +108,7 @@ various informational properties. This table describes performance states supported by a participant (typically the battery charger). -# ACPI Methods +## ACPI Methods The Active and Passive policies also provide for short Methods to define different kinds of temperature thresholds. @@ -141,7 +141,7 @@ a "graceful shutdown". These are optional, and are enabled by selecting the Critical Policy. -# How to use the devicetree entries +## How to use the devicetree entries The `drivers/intel/dptf` chip driver is organized into several sections: - Policies @@ -151,7 +151,7 @@ The `drivers/intel/dptf` chip driver is organized into several sections: The Policies section (`policies.active`, `policies.passive`, and `policies.critical`) is where the components of each policy are defined. -## Active Policy +### Active Policy Each Active Policy is defined in terms of 4 parts: 1) A Source (this is implicitly defined as TFN1, the system fan) @@ -182,7 +182,7 @@ the CPU's active cooling capability). When the CPU temperature first crosses rest of the table (note that it *must* be defined from highest temperature/ percentage on down to the lowest). -## Passive Policy +### Passive Policy Each Passive Policy is defined in terms of 5 parts: 1) Source - The device that can be throttled @@ -201,7 +201,7 @@ This example sets up a policy to begin throttling the charger performance when temperature sensor 1 reaches 65C. The sampling period here is 60000 ms (60 s). The Priority is defaulted to 100 in this case. -## Critical Policy +### Critical Policy Each Critical Policy is defined in terms of 3 parts: 1) Source - A device that can trigger a critical event @@ -218,7 +218,7 @@ register "policies.critical[1]" = "DPTF_CRITICAL(CPU, 75, SHUTDOWN)" This example sets up a policy wherein ACPI will cause the system to shutdown (in a "graceful" manner) when the CPU temperature reaches 75C. -## Power Limits +### Power Limits Control over the SoC's Running Average Power Limits (RAPL) is one of the tools that DPTF uses to enact Passive policies. DPTF can control both PL1 and PL2, if @@ -244,7 +244,7 @@ This example allow DPTF to control the SoC's PL1 level to between 3W and 15W, over a time interval ranging from 28 to 32 seconds, and it can move PL1 in increments of 200 mW. -## Charger Performance +### Charger Performance The battery charger can be a large contributor of unwanted heat in a system that has one. Controlling the rate of charging is another tool that DPTF uses to enact @@ -266,7 +266,7 @@ register "controls.charger_perf[3]" = "{ 8, 500 }" In this example, when DPTF decides to throttle the charger, it has four different performance states to choose from. -## Fan Performance +### Fan Performance When using DPTF, the system fan (`TFN1`) is the device responsible for actively cooling the other temperature sensors on the mainboard. A fan speed table can be @@ -298,21 +298,21 @@ increment of 10 percentage points. This is common when specifying fine-grained control of the fan, wherein DPTF will interpolate between the percentages in the table for a given temperature threshold. -## Options +### Options -### Fan +#### Fan 1) Fine-grained control - a boolean (see Fan Performance section above) 2) Step-size - Recommended minimum step size (in percentage points) to adjust the fan speed when using fine-grained control (ranges from 1 - 9). 3) Low-speed notify - If true, the platform will issue a `Notify (0x80)` to the fan device if a low fan speed is detected. -### Temperature sensors +#### Temperature sensors 1) Hysteresis - The amount of hysteresis implemented in either circuitry or the firmware that reads the temperature sensor (in degrees C). 2) Name - This name is applied to the _STR property of the sensor -## OEM Variables +### OEM Variables Platform vendors can define an array of OEM-specific values as OEM variables to be used under DPTF policy. There are total six OEM variables available. These can be used in AP policy for more specific actions. These OEM variables |