Operating system: Linux-5.4.0-26-generic-x86_64-with-debian-bullseye-sid 64 Bits
Graphics card: TITAN X (Pascal)/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 440.64
Broken: version: 2.80, 2.81, 2.82, 2.83 (c036ef136960)
Worked: Less noticeable in 2.80
Short description of error
When using Blender on Ubuntu / Xubuntu 20.04, whenever you switch to or away from something GPU Cycles related, Blender pins one CPU thread at 100% and the system hangs for a few seconds.
Some examples of this are:
- Switching from Solid to Rendered (and vice versa) in the Viewport
- Switching to the Render Properties when Cycles and GPU are set
- Starting a render with Cycles GPU
It seems that this occurs when Blender / Cycles needs to "probe" the gpu(s) in the system.
At least that's the best way I can describe it.
This behavior is absent on Xubuntu 18.04 on the same hardware.
In 2.80 the Blender UI merely freezes a few seconds, from 2.81 onward the entire desktop freezes and hitches.
Exact steps for others to reproduce the error
- Set Cycles to render on GPU (CUDA)
- Switch to rendered viewport / render any scene (Even on empty scenes this happens)