Not showing right background on all monitors; unresponsive, runs out of gpu memory with cosmic-bg not running

[ids1024]

I've noticed a weird slowness and crash, and it seems the issue was I didn't have cosmic-bg running...

Two issues here:

• The way backgrounds are handled requires cosmic-bg to be running to have ~/.local/state/cosmic/com.system76.CosmicBackground in a correct state. Not necessarily a problem to require cosmic-bg, but it should probably be handled more gracefully?
• The fact this causes a crash is presumably a iced_wgpu and/or wgpu issue, like Repeated drag-and-drop causes out-of-memory error in wgpu #40. But it's a weird thing to see...
  • gdb shows it's allocating wgpu buffers to upload image to the atlas. Not sure why caching isn't working, and only isn't working in this case?
  • buffer being leaked might be wgpu issue

[ids1024]

I'm also seeing this with the no-subsurfaces feature. Not sure what made this start happening. That used to work.

[ids1024]

iced-rs/iced#2425 sounds related.

[WatchMkr]

I noticed performance becomes really poor when wallpapers are set separately for each display.

[ids1024]

Yeah, I think that's the same issue. When I saw this, one output had the right background. I guess I hadn't had external monitors connected when I last ran cosmic-bg at the time.

Probably if we apply iced-rs/iced#2425 and resolve conflicts (or update our Iced) it will fixed it.

If the same image is used for all monitors, it's fine. But otherwise, it's being evicted from the cache when the next monitor is rendered. So it has to uploaded to GPU every frame.

The fact I saw this running out of GPU memory, though, suggests wgpu or iced_wgpu is also leaking buffers somewhere...

[ids1024]

686f4e7 should mitigate this. A future update to Iced should address the underlying problem.

[ids1024]

Although we may want to improve how things are handled in the future, this specific issue should be resolved for now.