Bug 405474

SUMMARY
I enabled 'Disable touchpad when mouse disconnected'.  I suspended the laptop and removed the mouse.  When I turned it back on again, I lost all pointer functionality.  I rebooted the laptop and discovered touchpad options were missing from system settings.  This issue persisted between reboots and made the laptop virtually useless.

Functionality restored only when mouse was connected and disconnected while unit was booted.  Having the mouse plugged in during boot did not fix the problem, although I at least had a usable mouse cursor.

STEPS TO REPRODUCE
1. Connect mouse
2. Enable 'Disable Touchpad when mouse connected'
3. Suspend Laptop
4. Disconnect mouse
5. Resume Laptop
6. Reboot laptop

OBSERVED RESULT
Total loss of touchpad functionality.  Hardware was non-responsive.  Touchpad settings were missing from Input Devices

EXPECTED RESULT
Touchpad works on resume, no loss of settings


SOFTWARE/OS VERSIONS
Windows: 
MacOS: 
Linux/KDE Plasma: Kubuntu 18.10
(available in About System)
KDE Plasma Version: 5.13.5
KDE Frameworks Version: 5.50
Qt Version: 5.11.1

ADDITIONAL INFORMATION

Enabling feature while mouse disconnected causes touchpad to become immediately unavailable, but the touchpad settings only disappear if the machine is rebooted.  Plugging in a USB mouse restores the touchpad settings.

This was extremely inconvenient and cost me a morning of productivity because my laptop was useless while I was travelling.  I can't even fathom how someone could think arbitrarily removing the touchpad settings would be a good idea.