Hi Lukasz,
On 02/10/2020 14:24, Lukasz Luba wrote: > Intelligent Power Allocation (IPA) is built around the PID controller > concept. The initialization code tries to setup the environment based on > the information available in DT or estimate the value based on minimum > power reported by each of the cooling device. The estimation will have an > impact on the PID controller behaviour via the related 'k_po', 'k_pu', > 'k_i' coefficients and also on the power budget calculation. > > This change prevents the situation when 'k_i' is relatively big compared > to 'k_po' and 'k_pu' values. This might happen when the estimation for > 'sustainable_power' returned small value, thus 'k_po' and 'k_pu' are > small. > > Signed-off-by: Lukasz Luba <[email protected]> > --- > drivers/thermal/gov_power_allocator.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/thermal/gov_power_allocator.c > b/drivers/thermal/gov_power_allocator.c > index 5cb518d8f156..f69fafe486a5 100644 > --- a/drivers/thermal/gov_power_allocator.c > +++ b/drivers/thermal/gov_power_allocator.c > @@ -131,6 +131,7 @@ static void estimate_pid_constants(struct > thermal_zone_device *tz, > int ret; > int switch_on_temp; > u32 temperature_threshold; > + s32 k_i; > > ret = tz->ops->get_trip_temp(tz, trip_switch_on, &switch_on_temp); > if (ret) > @@ -156,8 +157,11 @@ static void estimate_pid_constants(struct > thermal_zone_device *tz, > tz->tzp->k_pu = int_to_frac(2 * sustainable_power) / > temperature_threshold; > > - if (!tz->tzp->k_i || force) > - tz->tzp->k_i = int_to_frac(10) / 1000; > + if (!tz->tzp->k_i || force) { > + k_i = tz->tzp->k_pu / 10; > + tz->tzp->k_i = k_i > 0 ? k_i : 1; > + } I do not understand the rational behind this change. Do you have some values to share describing what would be the impact of this change? Depending on the thermal behavior of a board, these coefficients could be very different, no ? -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog
