Solved:    After more investigation, reinstalling the Xorg driver fixed the problem..  # dnf reinstall xorg-x11-server-Xorg

After successfully patching the NVIDIA 410.73 driver (see previous article), I encountered another problem at runtime, after # startx :

.....................................
[ 145.489] (II) Initializing extension GLX
[ 145.489] (II) AIGLX: Screen 0 is not DRI2 capable
[ 145.489] (EE) AIGLX: reverting to software rendering
[ 145.627] (II) IGLX: enabled GLX_MESA_copy_sub_buffer
[ 145.628] (EE)
[ 145.628] (EE) Backtrace:
[ 145.629] (EE) 0: /usr/libexec/Xorg (OsLookupColor+0x13d) [0x55839d3650ed]
[ 145.629] (EE) 1: /lib64/libpthread.so.0 (funlockfile+0x50) [0x7fdda5197fbf]
[ 145.630] (EE) 2: /usr/lib64/xorg/modules/extensions/libglx.so (GlxSetVisualConfigs+0x38b) [0x7fdda4923a6b]
[ 145.630] (EE) 3: /usr/lib64/xorg/modules/extensions/libglx.so (_init+0x1ac1d) [0x7fdda493d91d]
[ 145.630] (EE) 4: /usr/lib64/xorg/modules/extensions/libglx.so (_init+0x1a06d) [0x7fdda493c21d]
[ 145.630] (EE) 5: /usr/libexec/Xorg (InitExtensions+0x89) [0x55839d273d19]
[ 145.630] (EE) 6: /usr/libexec/Xorg (InitFonts+0x1f3) [0x55839d208c33]
[ 145.630] (EE) 7: /lib64/libc.so.6 (__libc_start_main+0xf3) [0x7fdda4fe3413]
[ 145.630] (EE) 8: /usr/libexec/Xorg (_start+0x2e) [0x55839d1f27be]
[ 145.630] (EE)
[ 145.630] (EE) Segmentation fault at address 0x7fdda34d3c18
[ 145.630] (EE)
Fatal server error:
[ 145.630] (EE) Caught signal 11 (Segmentation fault). Server aborting
[ 145.630] (EE)
[ 145.630] (EE)
Please consult the Fedora Project support
at http://wiki.x.org
for help.
[ 145.630] (EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information.
[ 145.630] (EE)
[ 145.878] (EE) Server terminated with error (1). Closing log file.

I found that the same happened with driver 410.57, and then tried older driver 396.54 – with the patch for Kernel 4.19 support – and that version worked correctly..  (Fedora 29, Kernel 4.19.0).

More research is needed, and I suspect it might be something ‘stale’ remaining from the F28-F29 upgrade?

Robert Gadsdon.  November 3, 2018.