This bug happens on ryzen 3400g with onboard graphics
the comment #23 solved my problem
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https://bugs.launchpad.net/bugs/1848741
Title:
[amdgpu] Ubuntu 19.10 horizontal graphics
Public bug reported:
An unresolvable problem occurred while calculating the upgrade.
This can be caused by:
* Upgrading to a pre-release version of Ubuntu
* Running the current pre-release version of Ubuntu
* Unofficial software packages not provided by Ubuntu
ProblemType: Bug
DistroRelease:
