Raspberry pi 命令'；xprintidle'；在systemd服务中返回非零退出状态1

我有一个带有Raspbian Buster Lite的Raspberry Pi，我用autologin在信息亭模式下启动。其目的是在连接的7英寸触摸屏（带铬）上显示单个网页。如果系统处于空闲状态，我的python脚本将检测到它并自动调暗屏幕。当用户再次与屏幕交互时，屏幕应再次亮起

这是我的剧本：

#!/usr/bin/env python3 import subprocess import time import sys from rpi_backlight import Backlight backlight = Backlight() # read arguments from the run command: # idle time before dim (in seconds) idleTimeBeforeDimMS = int( sys.argv[1] )*1000 # brightness when dimmed (between 0 and 100) brightnessDimmed = int( sys.argv[2] ) brightnessFull = 100 def get(cmd): # just a helper function return subprocess.check_output(cmd).decode("utf-8").strip() isIdle0 = False stateChanged = False timeIntervalToWatchChangesS = 100 / 1000 while True: time.sleep( timeIntervalToWatchChangesS ) currentIdleTimeMS = int( get("xprintidle") ) isIdle = currentIdleTimeMS > idleTimeBeforeDimMS stateChanged = isIdle0 != isIdle if isIdle and stateChanged: # idling backlight.brightness = brightnessDimmed elif not isIdle and stateChanged: # active backlight.brightness = brightnessFull # set current state as initial one for the next loop cycle isIdle0 = isIdle 如果我重新启动并运行sudo systemctl status dim_screen.service，我会得到以下结果：

我相信最重要的调试信息是这一行：

命令'xprintidle'返回非零退出状态1。

我觉得这很奇怪？如果我在终端中运行

xprintidle

，会发生以下情况：

pi@raspberrypi:~$ xprintidle 11399922 pi@raspberrypi：~$xprintidle 11399922 换句话说，我从

xprintidle

得到了一个有效的响应。我相信还有一些我不明白的事情

作为服务启动python脚本（

dim\u screen.py

）的正确方法是什么

pi@raspberrypi:~$ xprintidle 11399922