@@ -155,13 +155,11 @@ static void estimate_pid_constants(struct thermal_zone_device *tz,
if (!temperature_threshold)
return;
- if (!tz->tzp->k_po || force)
- tz->tzp->k_po = int_to_frac(sustainable_power) /
- temperature_threshold;
+ if (!tz->tzp->k_po_ratio || force)
+ tz->tzp->k_po_ratio = 1;
- if (!tz->tzp->k_pu || force)
- tz->tzp->k_pu = int_to_frac(2 * sustainable_power) /
- temperature_threshold;
+ if (!tz->tzp->k_pu_ratio || force)
+ tz->tzp->k_pu_ratio = 2;
if (!tz->tzp->k_i || force)
tz->tzp->k_i = int_to_frac(10) / 1000;
@@ -169,6 +167,11 @@ static void estimate_pid_constants(struct thermal_zone_device *tz,
* The default for k_d and integral_cutoff is 0, so we can
* leave them as they are.
*/
+
+ tz->tzp->k_po = int_to_frac(tz->tzp->k_po_ratio * sustainable_power) /
+ temperature_threshold;
+ tz->tzp->k_pu = int_to_frac(tz->tzp->k_pu_ratio * sustainable_power) /
+ temperature_threshold;
}
/**
@@ -202,6 +205,9 @@ static u32 pid_controller(struct thermal_zone_device *tz,
if (tz->tzp->sustainable_power) {
sustainable_power = tz->tzp->sustainable_power;
+ estimate_pid_constants(tz, sustainable_power,
+ params->trip_switch_on, control_temp,
+ false);
} else {
sustainable_power = estimate_sustainable_power(tz);
estimate_pid_constants(tz, sustainable_power,
@@ -284,13 +284,13 @@ struct thermal_zone_params {
* Proportional parameter of the PID controller when
* overshooting (i.e., when temperature is below the target)
*/
- s32 k_po;
+ s32 k_po, k_po_ratio;
/*
* Proportional parameter of the PID controller when
* undershooting
*/
- s32 k_pu;
+ s32 k_pu, k_pu_ratio;
/* Integral parameter of the PID controller */
s32 k_i;
k_po/k_pu are two proportional term constants and essentially they have fixed ratio compared with sustainable power. In current implementation, k_po and k_pu are absolute value after calculation and cannot represent the ratio relationship with sustainable power; as a result, when change sustainable power we cannot smoothly change proportional term constant. So this patch introduces variants k_po_ratio and k_pu_ratio, which represent the ratio value compared against sustainable power, so smaller ratio will result in thermal slower ramp. The formulas finally are as below: k_pu = k_pu_ratio * sustainable_power / (desired_temperature - switch_on_temp) k_po = k_po_ratio * sustainable_power / (desired_temperature - switch_on_temp) Signed-off-by: Leo Yan <leo.yan@linaro.org> --- drivers/thermal/power_allocator.c | 18 ++++++++++++------ include/linux/thermal.h | 4 ++-- 2 files changed, 14 insertions(+), 8 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/