用了官方的ubuntu和debian都试过了，风扇是淘宝5块钱的1.25接的fan口，然后一开机后就转，不能用pwm调节风扇的转速，一直是100%的速度在转，转的脑袋疼。刚开机的时候风扇是中速再转，然后过几秒后就全速转了。
刚刚进系统，没有启动pwm的时候(此时风扇已经100%在转了)
rock@rock-5b:~$ sudo cat /sys/kernel/debug/pwm
[sudo] password for rock:
platform/fd8b0010.pwm, 1 PWM device
pwm-0 ((null) ): period: 0 ns duty: 0 ns polarity: normal
然后使用命令
rock@rock-5b:~$ su root
Password:
root@rock-5b:/home/rock# echo 0 > /sys/devices/platform/fd8b0010.pwm/pwm/pwmchip*/export
echo 10000 > /sys/devices/platform/fd8b0010.pwm/pwm/pwmchip*/pwm0/period
echo 5000 > /sys/devices/platform/fd8b0010.pwm/pwm/pwmchip*/pwm0/duty_cycle
echo normal > /sys/devices/platform/fd8b0010.pwm/pwm/pwmchip*/pwm0/polarity
echo 1 > /sys/devices/platform/fd8b0010.pwm/pwm/pwmchip*/pwm0/enable
root@rock-5b:/home/rock#
风扇转速没有变化。。
此时
platform/fd8b0010.pwm, 1 PWM device (此时风扇还是100%在转了)
pwm-0 (sysfs ): requested enabled period: 10000 ns duty: 5000 ns polarity: normal
无论怎么调节duty_cycle, 风扇都是全力在转。请问工程师是硬件有问题吗
cpu温度一直是20多度
root@rock-5b:/sys/devices/platform/fd8b0010.pwm/pwm/pwmchip1/pwm0# cat *
cat: capture: Function not implemented
100
0
fixed
10000
normal
cat: power: Is a directory
root@rock-5b:/sys/devices/platform/fd8b0010.pwm/pwm/pwmchip1/pwm0# ls power
async autosuspend_delay_ms control runtime_active_kids runtime_active_time runtime_enabled runtime_status runtime_suspended_time runtime_usage
root@rock-5b:/sys/devices/platform/fd8b0010.pwm/pwm/pwmchip1/pwm0# cat power/*
disabled
cat: power/autosuspend_delay_ms: Input/output error
auto
0
0
disabled
unsupported
0
0
不插sd卡，风扇也狂转