implemented in kernel space (for instance Ethernet, serial or
mass storage) and other are implemented in user space.
+config USB_CONFIGFS_F_UAC1
+ boolean "Audio Class 1.0"
+ depends on USB_CONFIGFS
+ depends on SND
+ select USB_LIBCOMPOSITE
+ select SND_PCM
+ select USB_F_UAC1
+ help
+ This Audio function implements 1 AudioControl interface,
+ 1 AudioStreaming Interface each for USB-OUT and USB-IN.
+ This driver requires a real Audio codec to be present
+ on the device.
+
+config USB_CONFIGFS_F_UAC2
+ boolean "Audio Class 2.0"
+ depends on USB_CONFIGFS
+ depends on SND
+ select USB_LIBCOMPOSITE
+ select SND_PCM
+ select USB_F_UAC2
+ help
+ This Audio function is compatible with USB Audio Class
+ specification 2.0. It implements 1 AudioControl interface,
+ 1 AudioStreaming Interface each for USB-OUT and USB-IN.
+ This driver doesn't expect any real Audio codec to be present
+ on the device - the audio streams are simply sinked to and
+ sourced from a virtual ALSA sound card created. The user-space
+ application may choose to do whatever it wants with the data
+ received from the USB Host and choose to provide whatever it
+ wants as audio data to the USB Host.
+
source "drivers/usb/gadget/legacy/Kconfig"
endchoice