Felix Miata wrote:

> Anyone else have a perfectly working 16.04, upgrade to 18.04, then X
> segfaults? Neither TDE nor IceWM run because X doesn't get far enough
> along. Google hasn't found me anything on point as yet. :-(

obviously your problem is coming from GL, so look into this direction.
Disable or tune GL settings for the card or reinstall/install related.

[  1284.096] (EE) 9: /usr/lib/xorg/modules/extensions/libglx.so
(0x7fb96e825000+0x28907) [0x7fb96e84d907]
[  1284.096] (EE) 10: /usr/lib/xorg/modules/extensions/libglx.so
(0x7fb96e825000+0x2f8a1) [0x7fb96e8548a1]
[  1284.096] (EE) 11: /usr/lib/xorg/modules/extensions/libglx.so
(0x7fb96e825000+0x27305) [0x7fb96e84c305]


regards