xmir_screen_for_each_damaged_window iterates through all outputs on every frame (including unused ones)

[Daniel van Vugt]

xmir_screen_for_each_damaged_window iterates through all outputs (including unused ones), on every frame.

I thought it was a bit odd when debugging xmir_screen_for_each_damaged_window that it iterated through 6-8 different xmir_window's. I only have two outputs plugged in. The number actually grew over time (with display config changes?).

I think we should avoid iterating (or even creating) unused xmir_windows. In the very least it's inefficient to process all the damage reports more times than necessary.

Furthermore, I suspect the unused xmir_windows are accumulating damage that never gets emptied, which is probably bad.

[Daniel van Vugt (vanvugt)]

Dropping to Low importance. I haven't seen this cause any issues or have any noticeable performance impact.

[Daniel van Vugt (vanvugt)]

XMir 1.0 (the old Xorg extension) is now deprecated and is not being maintained or fixed. It is replaced by the new 'Xmir' binary (package 'xmir') introduced in Ubuntu 15.10 wily.