When IGD and DIS both exist in my pc,and I want to disable DIS,so I create a service to switch on and off the DIS.It works.Finally,I decide to add the service command into /etc/rc.local so that DIS will be powered off automatically.Unfortunately,it fails.There's only one command added by myself in the file /etc/rc.local,so I can affirm failure is caused by that added command. Before,I directly added the command "echo OFF /sys/kernel/debug..." into /etc/rc.local,and when I restarted,the system startup fails.So I thought maybe when the command is executed,the DIS hasn't been powered on or ready for work.So conflict occurs!It's just my prediction.Then I added one line command "sleep 1s" before the "echo OFF ...",it works nearly everytime when I start or restart pc,while fails sometimes. The output result of "cat /sys/kernel/debug..." is as following: 0:IGD:+:Pwr:0000:00:02.0 1:DIS: :Pwr:0000:01:00.0 I want know 0000:00:02.0 means what?Time of first power on? If it was really time,I can set the command "sleep 2s" to wait for DIS powered on then "echo OFF ..." Thanks for your advice!