since Kernel Version 5.9 the Display of my Thinkpad T570 with Intel Graphics stays dark after returning from suspend mode. If I look veeeeery carefully, I can see the Display itself is operating but only the light does not turn back on. I can blindly enter my Password and navigate to power off the Machine. After a reboot everything is back to normal until the next suspend.
This Problem only occurs with Kernel 5.9.*.
When I select 5.8.something in Grub everythin runs well.
Because I am not the experienced Linux User, I have no Idea how to start investigating this Problem.
Thanks in advance.