Also, I just tried Wine's dsound_test.exe with Wine's dsound.dll on Windows. On Windows it fails in IDirectSoundFullDuplex_tests() only, but test_COM() passes. On Wine test_COM() fails now, but works with 00211db0d08d60ee9a0e40206bf7cf9b5b88987b reverted. IMO it might mean that actually something is not working quite right with commit itself too, not just with its usage.