# How to turn on/off Raspberry Pi display? (permission errors) **URL:** \ **Category:** Scripts & Rules\ **Tags:** raspberry\ **Created:** [October 3, 2018, 10:41am UTC](https://community.openhab.org/t/how-to-turn-on-off-raspberry-pi-display-permission-errors/52861 "2018-10-03T10:41:35Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![StefanMUC](https://community.openhab.org/letter_avatar_proxy/v4/letter/s/da6949/32.png) [@StefanMUC](https://community.openhab.org/u/StefanMUC)\ **Post date:** [October 3, 2018, 10:41am UTC](https://community.openhab.org/t/how-to-turn-on-off-raspberry-pi-display-permission-errors/52861/1 "2018-10-03T10:41:35Z")
Hey there, as written in [HDMI Sleep - Raspberry Pi Forums](https://www.raspberrypi.org/forums/viewtopic.php?f=91&t=47550) i used »hdmi\_blanking=1« in my `/boot/config.txt` to put my display connected to the Pi to standby after Pi booted up. After »apt-get upgrade« and updating from openHAB 2.2 to 2.3 this doesn’t work anymore. - Platform information: - Hardware: Raspberry Pi 3 Model B - OS: openHABian - openHAB version: 2.3.0 So I thought: why not switch the display on/off through openHAB and be even more flexible. I have two scripts: `rpi-display-off.sh` ``` #!/bin/bash tvservice -o ``` `rpi-display-on.sh` ``` #!/bin/bash tvservice -p fbset -depth 8 fbset -depth 16 chvt 7 sleep .1 chvt 1 ``` They work quite well on console using `sudo` - but they don’t work with exec binding. So I followed [OpenHAB sudo [Exec Binding]](https://community.openhab.org/t/openhab-sudo-exec-binding/34988) to give `openhab` user sudo rights: > $ sudo -u openhab sudo -l > Matching Defaults entries for openhab on openHABianPi: > env\_reset, mail\_badpass, secure\_path=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin > > User openhab may run the following commands on openHABianPi: > (ALL) NOPASSWD: ALL (I know “ALL” is not good for productive use, one should restrict to necessary commands) But even with that, the scripts don’t work: > $ sudo -u openhab ./rpi-display-off.sh > [E] Failed to initialize VCHI (ret=-1) > $ sudo -u openhab ./rpi-display-on.sh > [E] Failed to initialize VCHI (ret=-1) > open /dev/fb0: Permission denied > open /dev/fb0: Permission denied > chvt: ioctl VT\_ACTIVATE: Operation not permitted > chvt: ioctl VT\_ACTIVATE: Operation not permitted So how do I turn my display on/off using openHAB? Thanks in advance! ---
**Author:** ![H102](https://community.openhab.org/user_avatar/community.openhab.org/h102/32/25595_2.png) [@H102](https://community.openhab.org/u/H102)\ **Post date:** [October 3, 2018, 12:10pm UTC](https://community.openhab.org/t/how-to-turn-on-off-raspberry-pi-display-permission-errors/52861/2 "2018-10-03T12:10:47Z")
Check the file with\> $ls -al /dev/fb0 Is your user added to this group and does the file have the correct permissions? ---
**Author:** ![StefanMUC](https://community.openhab.org/letter_avatar_proxy/v4/letter/s/da6949/32.png) [@StefanMUC](https://community.openhab.org/u/StefanMUC)\ **Post date:** [October 3, 2018, 2:01pm UTC](https://community.openhab.org/t/how-to-turn-on-off-raspberry-pi-display-permission-errors/52861/3 "2018-10-03T14:01:56Z")
Oh thanks, that looks good! > $ ls -al /dev/fb0 > crw-rw---- 1 root video 29, 0 Oct 3 12:10 /dev/fb0 So I added openhab to video group: > $ sudo usermod -a -G video openhab Now turning display on and off works (even without openhab in sudoers), but `rpi-display-on.sh` yields one last error: > $ sudo -u openhab ./rpi-display-on.sh > Powering on HDMI with preferred settings > chvt: ioctl VT\_ACTIVATE: Operation not permitted > chvt: ioctl VT\_ACTIVATE: Operation not permitted The `chvt` lines are needed in case of a double execute of the on script (otherwise screen is on but blank). What’s wrong here? ---
**Author:** ![StefanMUC](https://community.openhab.org/letter_avatar_proxy/v4/letter/s/da6949/32.png) [@StefanMUC](https://community.openhab.org/u/StefanMUC)\ **Post date:** [October 3, 2018, 2:06pm UTC](https://community.openhab.org/t/how-to-turn-on-off-raspberry-pi-display-permission-errors/52861/4 "2018-10-03T14:06:32Z")
Oh still can’t call the scripts with openHAB: > 2018-10-03 16:03:55.156 [INFO] [arthome.model.script.raspberry.rules] - Turning Raspberry display on > 2018-10-03 16:03:55.320 [INFO] [arthome.model.script.raspberry.rules] - [E] Failed to initialize VCHI (ret=-1) > open /dev/fb0: Permission denied > open /dev/fb0: Permission denied > chvt: ioctl VT\_ACTIVATE: Operation not permitted > chvt: ioctl VT\_ACTIVATE: Operation not permitted What’s going wrong here? I can use `sudo -u openhab` to run the scripts successfully, but opneHAB itself gets permission denied? weird. ---
**Author:** ![H102](https://community.openhab.org/user_avatar/community.openhab.org/h102/32/25595_2.png) [@H102](https://community.openhab.org/u/H102)\ **Post date:** [October 3, 2018, 2:35pm UTC](https://community.openhab.org/t/how-to-turn-on-off-raspberry-pi-display-permission-errors/52861/5 "2018-10-03T14:35:07Z")
From the terminal what’s the output of $groups Also check ls -al /etc/openhab2/scripts and make sure the scripts have correct permissions. ---
**Author:** ![StefanMUC](https://community.openhab.org/letter_avatar_proxy/v4/letter/s/da6949/32.png) [@StefanMUC](https://community.openhab.org/u/StefanMUC)\ **Post date:** [October 3, 2018, 8:28pm UTC](https://community.openhab.org/t/how-to-turn-on-off-raspberry-pi-display-permission-errors/52861/6 "2018-10-03T20:28:15Z")
Those are correct, as I set them previously. Scripts get executed - otherwise I wouldn’t see the error messages! > $ sudo -u openhab groups > openhab tty dialout audio video bluetooth gpio > $ ls -al |grep rpi > -rwxrwxr-x 1 openhab openhabian 25 Jul 12 22:51 rpi-display-off.sh > -rwxrwxr-x 1 openhab openhabian 80 Jul 12 23:16 rpi-display-on.sh Only difference is that `sudo -u openhab` can execute the script properly, but openhab can’t do that - why? ---
**Author:** ![H102](https://community.openhab.org/user_avatar/community.openhab.org/h102/32/25595_2.png) [@H102](https://community.openhab.org/u/H102)\ **Post date:** [October 3, 2018, 8:43pm UTC](https://community.openhab.org/t/how-to-turn-on-off-raspberry-pi-display-permission-errors/52861/7 "2018-10-03T20:43:50Z")
> [@StefanMUC](#): > > but openhab can’t do that - why? From where I’m sitting, can’t say for sure but shouldn’t openhabian be in sudo -u openhab groups. ---
**Author:** ![StefanMUC](https://community.openhab.org/letter_avatar_proxy/v4/letter/s/da6949/32.png) [@StefanMUC](https://community.openhab.org/u/StefanMUC)\ **Post date:** [October 3, 2018, 8:50pm UTC](https://community.openhab.org/t/how-to-turn-on-off-raspberry-pi-display-permission-errors/52861/8 "2018-10-03T20:50:07Z")
Solved it… as unspectacular as it could be: Restart openHAB service and now it runs (with known `chvt` error message). Seems as group memberships aren’t automatically aplied to running processes So if someone has a hint for `chvt` error message, I would be keen to try it. ---
**Author:** ![H102](https://community.openhab.org/user_avatar/community.openhab.org/h102/32/25595_2.png) [@H102](https://community.openhab.org/u/H102)\ **Post date:** [October 3, 2018, 8:58pm UTC](https://community.openhab.org/t/how-to-turn-on-off-raspberry-pi-display-permission-errors/52861/9 "2018-10-03T20:58:29Z")
Have you also used sudo systemctl daemon-reload since making your changes? ---
**Author:** ![sjcliffe](https://community.openhab.org/user_avatar/community.openhab.org/sjcliffe/32/22262_2.png) [@sjcliffe](https://community.openhab.org/u/sjcliffe)\ **Post date:** [October 4, 2018, 4:20am UTC](https://community.openhab.org/t/how-to-turn-on-off-raspberry-pi-display-permission-errors/52861/10 "2018-10-04T04:20:05Z")
I use: ``` vcgencmd display_power 1 ``` to turn video display on and: ``` vcgencmd display_power 0 ``` to turn if off. No sudo (root) required. ---
**Author:** ![bassysta](https://community.openhab.org/letter_avatar_proxy/v4/letter/b/bb73d2/32.png) [@bassysta](https://community.openhab.org/u/bassysta)\ **Post date:** [November 14, 2018, 11:50pm UTC](https://community.openhab.org/t/how-to-turn-on-off-raspberry-pi-display-permission-errors/52861/11 "2018-11-14T23:50:44Z")
Hi. I’ve tried your solution for the same problem, if i try: sudo -u openhab /script/monitorup.sh after added openhab to video group and rebooted raspberry, and the result is: Powering on HDMI with preferred settings chvt: ioctl VT\_ACTIVATE: Operation not permitted Screen power up but Blank. how have you soved it?