While testing the USB asynchronous audio MCU firmware, I discovered that VirtualBox changes the endpoint of asynchronous audio to synchronous. After some research, I found in the USBProxyDevice.cpp source file (/svn/vbox/trunk/src/VBox/Devices/USB/USBProxyDevice.cpp) the comment "Turn asynchronous audio endpoints into synchronous ones, see @bugref {8769}". Unfortunately, I could not find any other information about the reason for this substitution.
Could you please inform what is @bugref {8769}, and where I can get more detailed information on how to solve the problem of asynchronous audio in the VirtualBox guest OS.