One problem I've struggled with forever is the mouse cursor often disappearing after change of resolution or return from screenblank on my old athlon, with no way short of a reboot to bring it back.
I finally learned it is related to the nouveau video driver and my old nvidia graphics chipset. Once I knew this, I tried the nvidia-304 drivers, but they're not packaged for ubuntu 18 so I had to use nividia's installer. Anyways they were not reliable, they caused horiziontal lines a few cm wide to glitch on the screen, plus intermittent lockups.
So back to nouveau. I updated kernel to 4.20 cuz I don't fully understand what that does and seemed like there's nouveau stuff in the kernel and I figured it can't hurt, as I was on kernel 4.09 (bodhi legacy). But still same issue.
The solution was to create /etc/X11/xorg.conf and use option SWCursor. This disables the hardware mouse cursor; I haven't seen any ill effects since.
Code:
Section "Device"
Identifier "graphicsdriver"
Driver "nouveau"
Option "SWCursor" "true"
EndSection
So I'm pleased. Doubt this issue affects anyone else as it's pretty specific to my old hardware, but it was a problem I've asked about several times so glad it's finally resolved.