Flickering during login to Ubuntu 20.04 (vm)

[icecream102]

Issue/update/FYI: Logging in to Ubuntu 20.04 LTS Desktop, with GRUB-defined screen resolution 1920 x 1080, causes lots of flickering during the login.

Ref. “Please notify us if you confirm that it is resolved or open a new topic if you have the same problem.” for issue https://forums.nomachine.com/topic/screen-artifacts-black-flickering#post-26340

• Client: MacOS Big Sur, NoMachine client app “Version 7.7.4 (7.7.4)”
• Target machine: Ubuntu 20.04 LTS Desktop, “apt-upgraded” as of 2021-10-24, running as a virtual machine under Hyper-V on Windows Server 2016 DataCenter. (Gen. 2 vm, no live migrations, single-NUMA, nothing special at all)
• Graphics: The Hypervisor host (WS-2016) does not have a discrete graphics card. There is no GPU passthrough. It’s just a plain vm.

This tends to happen if the vm has been viewed via the Windows Hyper-V manager, before using NoMachine to attach to the vm. I suppose some screen is created by that action, and the log-in goes crazy due to the dual screens (of which both are virtual, to be precise – one provided by Hyper-V and the other by NoMachine).

 

 

[Carin]

Hi icecream102,

Can you tell us the following:
1. Is the flickering visible in the NoMachine session, in the Hyper-V manager, or both?

2. What desktop environment is it running in the virtual machine (Gnome Shell?) ?

3. What is the output when you run the command xrandr in the virtual machine?

Thanks!

[Author]

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