This MR consists of three fixes:
- A timeout calculation bug potentially causing us to end up in a semi-busy loop until the page flip FIFO became non-empty.
- A power saving issue where we in the past would potentially render in a semi-busy loop when power saving. Most likely seldom an issue, as redrawing requires damage, and we usually show the screen shield before power saving meaning no animation.
- Lack of power save handling in the FIFO-full handling (#509 (closed))