I updated a week ago the Tumbleweed system on my laptop and today to the latest
version 20200731. Since last week I get the Plasma login screen, but I can't
input any data from my keyboard. The mouse is working, both the touchpad and
when I plugin an USB mouse.
I have the same problem when using the Leap 15.2 system. But the Leap 15.1
works normal. I have some additional information from hwinfo:

Tumbleweed:
ltfctum:~ # hwinfo --keyboard
19: PS/2 00.0: 10800 Keyboard                                   
  [Created at input.226]
  Unique ID: nLyy.+49ps10DtUF
  Hardware Class: keyboard
  Model: "AT Translated Set 2 keyboard"
  Vendor: 0x0001 
  Device: 0x0001 "AT Translated Set 2 keyboard"
  Compatible to: int 0x0211 0x0001
  Device File: /dev/input/event0
  Device Files: /dev/input/event0,
/dev/input/by-path/platform-i8042-serio-0-event-kbd
  Device Number: char 13:64
  Driver Info #0:
    XkbRules: xfree86
    XkbModel: pc104
  Config Status: cfg=no, avail=yes, need=no, active=unknown

Leap 15.1:
ltfc151:~ # hwinfo --keyboard
19: PS/2 00.0: 10800 Keyboard                                   
  [Created at input.226]
  Unique ID: nLyy.+49ps10DtUF
  Hardware Class: keyboard
  Model: "AT Translated Set 2 keyboard"
  Vendor: 0x0001 
  Device: 0x0001 "AT Translated Set 2 keyboard"
  Compatible to: int 0x0211 0x0001
  Device File: /dev/input/event0
  Device Number: char 13:64
  Driver Info #0:
    XkbRules: xfree86
    XkbModel: pc104
  Config Status: cfg=no, avail=yes, need=no, active=unknown

The difference is in:
/dev/input/by-path/platform-i8042-serio-0-event-kbd