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@xxxxxxxxxx> --- Documentation/thermal/power_allocator.txt | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/Documentation/thermal/power_allocator.txt b/Documentation/thermal/power_allocator.txt index a1ce223..8958dab 100644 --- a/Documentation/thermal/power_allocator.txt +++ b/Documentation/thermal/power_allocator.txt @@ -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: -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
