I have a dual monitor setup running TTY only. The primary monitor is the actual "laptop", and the second monitor (Lilliput um-70) is connected through USB 2.0, using udl driver.

Everything is working fine, except for one thing, whenever I change TTY, the old TTY stops refreshing itself.

tty1 is mapped to /dev/fb0, tty2 is mapped to /dev/fb1 using kernel parameters during boot (fbcon=map:01). When I change to tty1 (laptop monitor), tty2 (USB monitor) stops refreshing.

For example, if I put an htop on tty2, going back to tty1 to do some stuff, the htop on tty2 freezes. If I go back to tty2, it refreshes itself, but tty1 now stops refreshing.

Any ideas on how to have tty1 and tty2 staying refreshed, no matter which TTY is active?

  • How do you switch between tty1 and tty2? with ALT+CTRL+F[1-2]?
    – Neticegear
    Dec 12, 2019 at 4:21
  • Yes. Or cycle using: CTRL+ALT + Arrow. Dec 12, 2019 at 9:23
  • Is your parameter fbcon=map:01? Because if so, try fbcon=map:10, or even fbcon=map:1 and then try mapping the consoles with con2fbmap afterwards
    – Neticegear
    Dec 12, 2019 at 14:34
  • Do you mean that this will fix the refreshing problem? I will try it when coming home. Dec 12, 2019 at 15:11
  • That is not working. Dec 14, 2019 at 19:35

1 Answer 1


One way to do this is to use a frambuffer terminal like Yaft (https://github.com/uobikiemukot/yaft).

This needs to be compiled with the config


in the conf.h file.

This allows for refreshing of the VT even if the VTs are inactive. For my specific hardware setup, I had to use the driver "udlfb" and NOT the newer driver "udl".

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.