BUG: Unity Editor hangs when handling DEVICELISTCHANGED callback

FMOD Engine
1

SETUP:
Alienware m17 laptop
Windows 10
Unity 2019.4.36f1
FMOD (UnityAudio disabled)

PROBLEM: Unity Editor hangs during DEVICELISTCHANGED callback if FMOD API is accessed. Specifically, the endpoints are:

  • CoreSystem.getDriver
  • CoreSystem.getNumDrivers
  • CoreSystem.getDriverInfo

Attaching debugger shows that the stuck call is:
RuntimeManager.DrawDebugOverlay (Line 728) => Memory.GetStats(Line 924), called with blocking = true.

Callback was triggered by switching system device.

No other calls appear to be stuck and FMOD music continues to play.

2

FAILED WORK AROUND: Disable stats. Registered callback is not received, and program hangs in editor when playing is stopped. While playing switching devices cause problems indicated by console warning:

[FMOD] AsyncCommandBuffer::growBuffer : Growing command buffer to 524288 bytes. Initial command buffer size can be tuned to avoid dynamic growth using Studio::System::setAdvancedSettings()

UnityEngine.Debug:LogWarning (object)

FMODUnity.RuntimeUtils:DebugLogWarning (string) (at Assets/Plugins/FMOD/src/RuntimeUtils.cs:533)

FMODUnity.RuntimeManager:DEBUG_CALLBACK (FMOD.DEBUG_FLAGS,intptr,int,intptr,intptr) (at Assets/Plugins/FMOD/src/RuntimeManager.cs:86)

FMOD.Studio.System:getBus (string,FMOD.Studio.Bus&) (at Assets/Plugins/FMOD/src/fmod_studio.cs:444)

FMODUnity.RuntimeManager:ApplyMuteState () (at Assets/Plugins/FMOD/src/RuntimeManager.cs:1447)

FMODUnity.RuntimeManager:Update () (at Assets/Plugins/FMOD/src/RuntimeManager.cs:537)

WORKAROUND: Set (in a thread-safe way) a flag to trigger updating devices on the main Unity thread.

3

I have not noticed any hangs when calling the FMOD API inside a DEVICELISTCHANGED callback. How long is it hanging for?
Would it be possible for you to share a code snippet of your callback?