Dear Maintainer,

*** Reporter, please consider answering these questions, where appropriate ***

   * What led up to the situation?

with a new installation of Debian 10 (as well after an upgrade to Debian
9 which I skipped due to this problem, I have a dual boot system) the X
servers did not start properly anymore as with Debian 8. I got a
segmentation fault announced.

References

https://lists.debian.org/debian-x/2019/07/msg00069.html
Threads in the xorg mailing lists are
https://lists.x.org/archives/xorg/2019-July/059852.html
https://lists.x.org/archives/xorg/2019-August/059876.html
The discussion there contains logfiles.

Due to suggestions given by the xorg mailing list I found to
configuration items that avoid the failure:

a) introducing

       Option      "DRI" "False"

b) choosing explicitely a colour depth like 8

       SubSection "Display"
               Viewport   0 0
               Depth     8
       EndSubSection

Best regards
Markus Hiereth