ASUS G752VS i7-6820HK @ 2.70GHz, 32GB RAM, Nvidia GeForce GTX 1070 (8GB GDDR5 VRAM)
OS Windows 10 Professional, 64bit (NOT the Anniversary update 1607)
Broken: Blender 2.78b [Hash: 9cb21a1] portable 64bit (blender-2.78b-windows64.zip)
Worked: Blender 2.78.4 [Hash: f7eaaf3] portable 64bit (blender-2.78-f7eaaf3-win64.zip)
Short description of error
The Auto Tile Size add-on displays a warning message and a button to fix an issue but instead it generates error messages and a continuous loop of them inside the Blender's system console.
Exact steps for others to reproduce the error
With the Auto Tile Size add-on is enabled, the Cycles Compute Device set to CUDA with the GeForce GTX 1070 set in Preferences, and the Render Device set to GPU in the Render panel, the Auto Tile Size info panel under Performance displays a warning on a button named "Device changed - fix" as shown below
Clicking on that button to apparently fix the issue generates the following Python errors (in reverse order, from bottom to top, I cutted and pasted it from the Info log panel):
Traceback (most recent call last):
File "D:\Blender_2.78_stable\2.78\scripts\addons\render_auto_tile_size.py", line 336, in execute if do_set_tile_size(context): File "D:\Blender_2.78_stable\2.78\scripts\addons\render_auto_tile_size.py", line 278, in do_set_tile_size choice = getattr(settings, get_tilesize_prop(engine, device, userpref)) File "D:\Blender_2.78_stable\2.78\scripts\addons\render_auto_tile_size.py", line 154, in get_tilesize_prop if engine_is_gpu(engine, device, userpref): File "D:\Blender_2.78_stable\2.78\scripts\addons\render_auto_tile_size.py", line 149, in engine_is_gpu return engine == 'CYCLES' and device == 'GPU' and userpref.system.compute_device_type != 'NONE'
AttributeError: 'UserPreferencesSystem' object has no attribute 'compute_device_type'
location: <unknown location>:-1
Furthermore, in the Blender's system console the above messages are continuously looping and stops only when switching the render device from GPU back to CPU.
I noticed this same behavior for this add-on also with the official 2.78a version but not with the later versions downloaded from the blender buildbot (daily builds). For completeness of information I downloaded the currently available developmental build, portable Windows 64bit [Hash: f7eaaf3] and the add-on works perfectly without any warning or errors.