Hard lockups during drag+drop on GTX 1060

I’m experiencing some sporadic performance issues on my 1060 when having KDE’s Desktops effects disabled. One of the best reproducible issues happens when dragging a selection of text around in Firefox.

Reproducible with: 384.111, 387.34 and 390.12

Steps to reproduce:

  1. Start KDE
  2. Disable Desktop Effects (effectively by pressing ALT+SHIFT+F12)
  3. Start Firefox
  4. Open some webpage like [url]https://en.wikipedia.org/wiki/Nvidia[/url] or [url]https://hcs64.com/mboard/forum.php[/url]
  5. Select some text, drag and drop it around

Please find a screen recording demonstrating this issue attached. I start dragging some selected text having Desktop Effects disabled. Although I quickly release the mouse shortly after dragging, the screen as well as the mouse cursor freezes for several seconds. After the system responds again, I re-enable desktop effects and demonstrate the dragging again, which works fine in this case. In rare cases depending on the kind of selection, the freeze can take up to one minute.

My System:
GTX 1060 6GB
OpenSuse 42.3 x86_64
KDE Plasma Version: 5.8.7
KDE Frameworks Version: 5.32.0
Qt Version: 5.6.2
Firefox ESR 52.6.0

nvidia-bug-report.log.gz (110 KB)
framerate_problem.mkv.tar (6.65 MB)