I'm regularly having a problem where my laptop on resuming from a sleep has plasma completely unresponsive, taskbar shows but does not respond to clicks, and does not update when an application exits, desktop is completely black, background picture does not show and neither do any of the widgets. Alt-tab still works, allowing me to use already running instances of Konsole, Kmail, Libreoffice, Firefox, etc, without issues.

Laptop has been through various Kubuntu releases, dist-upgraded for the last 2 years. 10.10 did not exhibit any issues.

Hardware: Toshiba Satellite P300-1C9.

Anyone else seeing this?

Does anyone know the best way to help debug this?

Thanks