KDE via startx locks up before startup completes

[Felix Miata]

P4 2.8G, no hyperthreading, with i865G video.

F20 and F21 work normally.

Kernel 3.19.0-0.rc3.git1.2.fc22.i686+PAE on an i686
xorg-x11-drv-intel-2.99.917-2.fc22.i686
xorg-x11-server-Xorg-1.16.2.901-1.fc22.i686

Installing libinput didn't help.
Chmod 4711 /usr/bin/Xorg didn't help.

KDE in F22 works fine via KDM, but after 2nd icon paints starting from
startx, either plain without KDM running, or after logging in via KDM then
from a vty startx -- :1, the machine hard locks, no input from mouse or
keyboard is possible, and remote login dies.

If I do startx -- :1 from Konsole, I get dumped to a black screen, but
keyboard works to switch among all ttys, showing either login prompts, shell
prompt, or a cursor in upper left corner of an otherwise all black screen.
Top on the remote login remains active showing a single Xorg.bin,
plasma-desktop and krunner each.

I can't seem to find any clues about the lockups in dmesg, Xorg.0.log,
elsewhere in /var/log/ or from journalctl.
-- 
"The wise are known for their understanding, and pleasant
words are persuasive." Proverbs 16:21 (New Living Translation)

 Team OS/2 ** Reg. Linux User #211409 ** a11y rocks!

Felix Miata  ***  http://fm.no-ip.com/