Comment # 5 on bug 100666 from Lucas Riutzel

$ ls /sys/class/drm/card*/device/hwmon/hwmon*/pwm*

/sys/class/drm/card0/device/hwmon/hwmon0/pwm1
/sys/class/drm/card0/device/hwmon/hwmon0/pwm1_enable
/sys/class/drm/card0/device/hwmon/hwmon0/pwm1_max
/sys/class/drm/card0/device/hwmon/hwmon0/pwm1_min