1.问题现象： 当电量低于10%时，卡住或运行缓慢。
2.问题原因分析： 当功率足够时，输入命令 cat /sys/devices/system/cpu/cpufreq/policy0/cpuinfo_cur_freq ，结果是2016000；当电量低于10%时，结果是1305600。
It’s nomal . This is thermal BCL feature which can mitigate the current drawn from the battery by reducing the CPU load and ensures that OCP and UVLO do not occur. it can make system stable.
soc { polling-delay-passive = <100>; polling-delay = <0>; thermal-governor = “low_limits_cap”; thermal-sensors = <&bcl_soc>; wake-capable-sensor; tracks-low;
trips { pmi632_low_soc: low-soc { temperature = <10>; // //the threshold here is not temperature for BCL, it’s the battery capacity, 10% here // you can change it to 0 , 1, 2, … as you like. hysteresis = <0>; type = “passive”; }; }; };
在低功率的情况下，有没有办法放松？CPU频率限制。目前，当低功率降低到1305600时，系统将卡住或关闭并重新启动，影响其他测试。CPU降频时，系统仍能正常运行，如设置13056000低频率~2016000的一个值，让系统不会崩溃卡死？ You can search bcl in your project dtsi, and modify in cooling-device
80-P9301-113_C_Thermal_Core_Overview section: BCL Thermal Zones BCL Device Tree
example:
soc { polling-delay-passive = <100>; polling-delay = <0>; thermal-governor = “low_limits_cap”; thermal-sensors = <&bcl_sensor 5>; tracks-low;
trips { pm660_low_soc: low-soc { temperature = <10>; hysteresis = <0>; type = “passive”; }; }; cooling-maps { soc_map6 { trip = <&pm660_low_soc>; cooling-device = -<&CPU6 THERMAL_MAX_LIMIT -THERMAL_MAX_LIMIT>; <&CPU6 (THERMAL_MAX_LIMIT-1) (THERMAL_MAX_LIMIT-1)>; }; soc_map7 { trip = <&pm660_low_soc>; cooling-device = <&CPU7 THERMAL_MAX_LIMIT THERMAL_MAX_LIMIT>; }; }; };
附：老平台如SDM660遇到这样的问题怎么办？ \LA.UM.8.2\kernel\msm-4.4\arch\arm64\boot\dts\qcom\sdm660.dtsi qcom,bcl { compatible = “qcom,bcl”; qcom,bcl-enable; ====>>删除此行验证 qcom,bcl-framework-interface; qcom,bcl-hotplug-list = <&CPU6 &CPU7>; qcom,bcl-soc-hotplug-list = <&CPU4 &CPU5 &CPU6 &CPU7>; qcom,ibat-monitor { qcom,low-threshold-uamp = <3400000>; qcom,high-threshold-uamp = <4200000>; qcom,vph-high-threshold-uv = <3500000>; qcom,vph-low-threshold-uv = <3300000>; qcom,soc-low-threshold = <10>; }; }; 这是高通的低电降低cpu频率的feature，关掉就好了