@@ -114,13 +114,20 @@ whilst temperature is low, and may lead to temperature overshooting.
The default value for `k_pu` is:
- 2 * sustainable_power / (desired_temperature - switch_on_temp)
+ k_pu_ratio * sustainable_power / (desired_temperature - switch_on_temp)
This means that at `switch_on_temp` the output of the controller's
-proportional term will be 2 * `sustainable_power`. The default value
-for `k_po` is:
+proportional term will be k_pu_ratio * `sustainable_power`.
- sustainable_power / (desired_temperature - switch_on_temp)
+The default value for `k_po` is:
+
+ k_po_ratio * sustainable_power / (desired_temperature - switch_on_temp)
+
+k_pu_ratio's default value is 2 and k_po_ratio's default value is 1.
+These two vairants mean the ratio value compared against sustainable power,
+so smaller ratio will result in thermal slower ramp. User can set these two
+ratio value from sys filesystem nodes, finally k_pu and k_po will be
+calculated by updated ratio value.
Focusing on the proportional and feed forward values of the PID
controller equation we have:
Document k_pu_ratio and k_po_ratio's purpose, and refine formula to demonstrate to use ratio to calculate k_pu/k_po. Signed-off-by: Leo Yan <leo.yan@linaro.org> --- Documentation/thermal/power_allocator.txt | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/