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-rw-r--r--Documentation/driver-api/thermal/power_allocator.rst12
1 files changed, 11 insertions, 1 deletions
diff --git a/Documentation/driver-api/thermal/power_allocator.rst b/Documentation/driver-api/thermal/power_allocator.rst
index 67b6a3297238..aa5f66552d6f 100644
--- a/Documentation/driver-api/thermal/power_allocator.rst
+++ b/Documentation/driver-api/thermal/power_allocator.rst
@@ -71,7 +71,9 @@ to the speed-grade of the silicon. `sustainable_power` is therefore
simply an estimate, and may be tuned to affect the aggressiveness of
the thermal ramp. For reference, the sustainable power of a 4" phone
is typically 2000mW, while on a 10" tablet is around 4500mW (may vary
-depending on screen size).
+depending on screen size). It is possible to have the power value
+expressed in an abstract scale. The sustained power should be aligned
+to the scale used by the related cooling devices.
If you are using device tree, do add it as a property of the
thermal-zone. For example::
@@ -269,3 +271,11 @@ won't be very good. Note that this is not particular to this
governor, step-wise will also misbehave if you call its throttle()
faster than the normal thermal framework tick (due to interrupts for
example) as it will overreact.
+
+Energy Model requirements
+=========================
+
+Another important thing is the consistent scale of the power values
+provided by the cooling devices. All of the cooling devices in a single
+thermal zone should have power values reported either in milli-Watts
+or scaled to the same 'abstract scale'.