cRIO Display Port is Disabled When a Monitor is Disconnected and Reconnected

Updated May 3, 2018

Reported In

Hardware

  • cRIO-9039
  • cRIO-9037
  • cRIO-9038
  • cRIO-9036
  • cRIO-9034

Operating System

  • NI Linux Real-Time

Issue Details

The display port on my cRIO is disabled when I disconnect and reconnect a monitor, how can I re-enable the port without power cycling my device? 

Solution

LabVIEW 2017:
Run the command xrandr --display :0 --auto from a script or within LabVIEW; it will re-run the system's auto-detection and the Embedded UI should appear on the monitor. The command doesn't need special privileges and can be run as lvuser.

LabVIEW 2015 or LabVIEW 2015 SP1:
1. Download the attached 80-video-hotplug.rules file
2. Log in to your cRIO as an administrator (the folder you will need to access are system folders, so otherwise it will not work)
3. Copy the file to /etc/udev/rules.d/
4. Restart your cRIO

You may now disconnect/reconnect the display from the cRIO and the Embedded UI will reappear on your monitor.

Alternatively, you can also create the file via SSH:
1. Log into your cRIO via SSH as an administrator
2 . Copy the following line into the console:
cd /etc/udev/rules.d/ && echo 'ACTION=="change", SUBSYSTEM=="drm", RUN+="/usr/bin/xrandr --auto --display :0"' >80-video-hotplug.rules
3. Confirm the file has been created in the correct location and restart the cRIO

For debugging purposes you can monitor what events are received by udev by running the following command as admin: udevadm monitor.

 

Additional Information

This is a known issue of the Embedded UI, which is a feature available on the NI Linux Real-Time Intel x64-based targets. Disconnecting the display from the cRIO Mini DisplayPort causes the Embedded UI to disappear and the display adapter cannot detect the display after it has been reconnected to the cRIO.

This has since been resolved following kernel updates in 2018.

 

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