AIBOX-1684X 风扇工作策略调节
本文前言：测试 AIBOX-1684X 开发板风扇工作策略调节
风扇工作策略
AIBOX-1684X 风扇工作分为 5 个等级：
| 主控当前温度 | 风扇工作等级 |
|---|---|
| ≥ 33℃ | 1 |
| ≥ 55℃ | 2 |
| ≥ 60℃ | 3 |
| ≥ 65℃ | 4 |
| ≥ 70℃ | 5 |
风扇工作等级越高，转速越快，如果主控当前温度低于 33℃，风扇默认是关闭状态。
用户可通过执行以下命令查看当前主控的工作温度：
cat /sys/class/thermal/thermal_zone1/temp
例如以下是 45.5 ℃：
cat /sys/class/thermal/thermal_zone1/temp 45500
另外，用户也可以自己手动打开风扇（写入 0-5， 0 是关闭， 5 是最大等级）：
sudo -i echo 4 > /sys/class/thermal/cooling_device0/cur_state
除了手册上的分等级控制方法之外，find /sys -iname '*fan*' -o -iname 'pwm*' 2>/dev/null | sed -n '1,120p'，完整LOGS显示
/sys/class/pwm /sys/class/pwm/pwmchip0 /sys/devices/platform/pinctrl@50010400/pinmux/bm_pinmux/pwm1 /sys/devices/platform/pinctrl@50010400/pinmux/bm_pinmux/fan0 /sys/devices/platform/pinctrl@50010400/pinmux/bm_pinmux/fan1 /sys/devices/platform/pinctrl@50010400/pinmux/bm_pinmux/pwm0 /sys/devices/platform/50029000.pwm/pwm /sys/devices/platform/50029000.pwm/pwm/pwmchip0 /sys/devices/platform/pwm-fan /sys/devices/platform/pwm-fan/hwmon/hwmon1/pwm1 /sys/devices/virtual/bm-tach/bm-tach-0/fan_speed /sys/bus/platform/devices/pwm-fan /sys/bus/platform/drivers/pwm-fan /sys/bus/platform/drivers/pwm-fan/pwm-fan /sys/firmware/devicetree/base/thermal-zones/soc/trips/soc_pwmfan_trip@4 /sys/firmware/devicetree/base/thermal-zones/soc/trips/soc_pwmfan_trip@2 /sys/firmware/devicetree/base/thermal-zones/soc/trips/soc_pwmfan_trip@3 /sys/firmware/devicetree/base/thermal-zones/soc/trips/soc_pwmfan_trip@1 /sys/firmware/devicetree/base/pinctrl@50010400/pwm1_release /sys/firmware/devicetree/base/pinctrl@50010400/fan1_release /sys/firmware/devicetree/base/pinctrl@50010400/pwm0_acquire /sys/firmware/devicetree/base/pinctrl@50010400/fan0_acquire /sys/firmware/devicetree/base/pinctrl@50010400/pwm0_release /sys/firmware/devicetree/base/pinctrl@50010400/fan0_release /sys/firmware/devicetree/base/pinctrl@50010400/pwm1_acquire /sys/firmware/devicetree/base/pinctrl@50010400/fan1_acquire /sys/firmware/devicetree/base/pwm-fan /sys/firmware/devicetree/base/pwm-fan/pwm-names /sys/firmware/devicetree/base/pwm-fan/pwms /sys/firmware/devicetree/base/pwm-fan/pwm_inuse /sys/firmware/devicetree/base/pwm@50029000 /sys/firmware/devicetree/base/pwm@50029000/pwm-num /sys/module/smifb/parameters/pwm /sys/module/rcutree/parameters/rcu_fanout_leaf /sys/module/rcutree/parameters/rcu_fanout_exact其中，与风扇控制相关的LOGS
- PWM 输出： - `/sys/devices/platform/pwm-fan/hwmon/hwmon1/pwm1` - 转速反馈： - `/sys/devices/virtual/bm-tach/bm-tach-0/fan_speed`说明pwm值可以单独现实，查看当前pwm和speed数值
cat /sys/devices/platform/pwm-fan/hwmon/hwmon1/pwm1 cat /sys/devices/virtual/bm-tach/bm-tach-0/fan_speed设置指令
echo 64 | sudo tee /sys/devices/platform/pwm-fan/hwmon/hwmon1/pwm1但是值得注意的是，这台机器还有一个线索值得看：
- `/sys/firmware/devicetree/base/thermal-zones/soc/trips/soc_pwmfan_trip@*`这说明它可能有自动温控策略，所以如果你手动写完 PWM 又被系统改回去，也不奇怪。