kde does not start normally

[Carlos Kosloff]

If you follow this list you are aware of my efforts to get kde to start 
normally.
I am aware that many of you have succeeded, maybe some did not, I am 
among the latter.
Different systems and hardware react differently, I have a computer that 
works fine with sddm, but in my main system sddm throws a black screen, 
and both have similar configurations.
My question is: can somebody help with making kde start normally?
So far no dm has worked, I am forced to start kde with "startx startkde".
Thank you.
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