Linux UAC2 功能的设备描述符
可能内核有所更新，描述符有些细节会不一样，但总体不会有太多区别，放在这里方便查询
UAC2 descriptor
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
idVendor 0x2207
idProduct 0x0019
bcdDevice 2.00
iManufacturer 1 rockchip
iProduct 2 USB Audio Device
iSerial 3 0123456789ABCDEF
bNumConfigurations 1
Configuration Descriptor: //配置描述符，置描述符之后紧接着就是接口描述符，接口描述符指明了接口的类型，对应的端点的数量
bLength 9
bDescriptorType 2
wTotalLength 219
bNumInterfaces 3
bConfigurationValue 1
iConfiguration 4 audio
bmAttributes 0x80
(Bus Powered)
MaxPower 500mA
Interface Association: USB复合设备一般用Interface Association Descriptor（IAD）实现，就是在要合并的接口前加上IAD描述符
bLength 8
bDescriptorType 11 //IAD描述符类型
bFirstInterface 0 //起始接口
bInterfaceCount 3 //接口数
bFunctionClass 1 Audio //类型代码
bFunctionSubClass 0 //子类型代码
bFunctionProtocol 32 //协议代码
iFunction 5 Source/Sink //描述符字符串索引
Interface Descriptor:
bLength 9
bDescriptorType 4 //描述符类型
bInterfaceNumber 0 //接口数
bAlternateSetting 0 //bAlternateSetting用于在同一个接口中的多个描述符中进行切换
bNumEndpoints 0 //端点数
bInterfaceClass 1 Audio
bInterfaceSubClass 1 Control Device
bInterfaceProtocol 32
iInterface 6 Topology Control
AudioControl Interface Descriptor: //音频设备接口标题中要包含类特定的AC接口头描述符，用于定义接口的其他功能端口。类特定的AC接口头描述符（AC接口头）
bLength 9
bDescriptorType 36 //恒定配置法定类型 USB_DTYPE_CS_INTERFACE
bDescriptorSubtype 1 (HEADER) //数字AC接口头
bcdADC 2.00 //数字音频设备发行码
bCategory 8
wTotalLength 83 //数字连接长度总长度，包括标准接口长度
bmControl 0x00
AudioControl Interface Descriptor: //音频设备频率描述/* Clock source for IN traffic */
bLength 8
bDescriptorType 36
bDescriptorSubtype 10 (CLOCK_SOURCE)
bClockID 6 //bClockID号
bmAttributes 0x01 Internal fixed Clock
bmControls 0x01
Clock Frequency Control (read-only)
bAssocTerminal 0 //恒定对应输出端口ID
iClockSource 7 48000Hz
AudioControl Interface Descriptor: //音频设备频率描述 Clock source for OUT traffic
bLength 8
bDescriptorType 36
bDescriptorSubtype 10 (CLOCK_SOURCE)
bClockID 5 //bClockID号
bmAttributes 0x01 Internal fixed Clock
bmControls 0x01
Clock Frequency Control (read-only)
bAssocTerminal 0
iClockSource 8 64000Hz
AudioControl Interface Descriptor: //音频设备的输入端口描述符， Input Terminal for USB_OUT
bLength 17
bDescriptorType 36
bDescriptorSubtype 2 (INPUT_TERMINAL)
bTerminalID 1 //端口号ID
wTerminalType 0x0101 USB Streaming
bAssocTerminal 0 //恒定对应输出端口ID
bCSourceID 5
bNrChannels 2 //通道数
bmChannelConfig 0x00000003 //数字通道配置
Front Left (FL)
Front Right (FR)
bmControls 0x0003
Copy Protect Control (read/write)
iChannelNames 0
iTerminal 9 USBH Out
AudioControl Interface Descriptor: //Input Terminal for I/O-In
bLength 17
bDescriptorType 36
bDescriptorSubtype 2 (INPUT_TERMINAL)
bTerminalID 2
wTerminalType 0x0201 Microphone
bAssocTerminal 0
bCSourceID 6
bNrChannels 2
bmChannelConfig 0x00000003
Front Left (FL)
Front Right (FR)
bmControls 0x0003
Copy Protect Control (read/write)
iChannelNames 0
iTerminal 10 USBD Out
AudioControl Interface Descriptor: //Ouput Terminal for USB_IN
bLength 12
bDescriptorType 36
bDescriptorSubtype 3 (OUTPUT_TERMINAL)
bTerminalID 4
wTerminalType 0x0101 USB Streaming
bAssocTerminal 0
bSourceID 2
bCSourceID 6
bmControls 0x0003
Copy Protect Control (read/write)
iTerminal 11 USBH In
AudioControl Interface Descriptor: //Ouput Terminal for I/O-Out
bLength 12
bDescriptorType 36
bDescriptorSubtype 3 (OUTPUT_TERMINAL)
bTerminalID 3
wTerminalType 0x0301 Speaker
bAssocTerminal 0
bSourceID 1
bCSourceID 5
bmControls 0x0003
Copy Protect Control (read/write)
iTerminal 12 USBD In
Interface Descriptor: //Audio Streaming OUT Interface - Alt0
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 0
bNumEndpoints 0
bInterfaceClass 1 Audio
bInterfaceSubClass 2 Streaming
bInterfaceProtocol 32
iInterface 13 Playback Inactive
Interface Descriptor: //Audio Streaming OUT Interface - Alt1
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 1
bNumEndpoints 1
bInterfaceClass 1 Audio
bInterfaceSubClass 2 Streaming
bInterfaceProtocol 32
iInterface 14 Playback Active
AudioStreaming Interface Descriptor: //Audio Stream OUT Intface Desc
bLength 16
bDescriptorType 36
bDescriptorSubtype 1 (AS_GENERAL)
bTerminalLink 1
bmControls 0x00
bFormatType 1
bmFormats 0x00000001
PCM
bNrChannels 2
bmChannelConfig 0x00000003
Front Left (FL)
Front Right (FR)
iChannelNames 0
AudioStreaming Interface Descriptor: /* Audio USB_OUT Format */
bLength 6
bDescriptorType 36
bDescriptorSubtype 2 (FORMAT_TYPE)
bFormatType 1 (FORMAT_TYPE_I)
bSubslotSize 2
bBitResolution 16
Endpoint Descriptor: /* STD AS ISO OUT Endpoint */
bLength 7
bDescriptorType 5
bEndpointAddress 0x00 EP 2 OUT
bmAttributes 9
Transfer Type Isochronous
Synch Type Adaptive
Usage Type Data
wMaxPacketSize 0x0100 1x 256 bytes
bInterval 1
AudioControl Endpoint Descriptor: /* CS AS ISO OUT Endpoint */
bLength 8
bDescriptorType 37
bDescriptorSubtype 1 (EP_GENERAL)
bmAttributes 0x00
bmControls 0x00
bLockDelayUnits 0 Undefined
wLockDelay 0
Interface Descriptor: /* Audio Streaming IN Interface - Alt0 */
bLength 9
bDescriptorType 4
bInterfaceNumber 2
bAlternateSetting 0
bNumEndpoints 0
bInterfaceClass 1 Audio
bInterfaceSubClass 2 Streaming
bInterfaceProtocol 32
iInterface 15 Capture Inactive
Interface Descriptor: /* Audio Streaming IN Interface - Alt1 */
bLength 9
bDescriptorType 4
bInterfaceNumber 2
bAlternateSetting 1
bNumEndpoints 1
bInterfaceClass 1 Audio
bInterfaceSubClass 2 Streaming
bInterfaceProtocol 32
iInterface 16 Capture Active
AudioStreaming Interface Descriptor: /* Audio Stream IN Intface Desc */
bLength 16
bDescriptorType 36
bDescriptorSubtype 1 (AS_GENERAL)
bTerminalLink 4
bmControls 0x00
bFormatType 1
bmFormats 0x00000001
PCM
bNrChannels 2
bmChannelConfig 0x00000003
Front Left (FL)
Front Right (FR)
iChannelNames 0
AudioStreaming Interface Descriptor: /* Audio USB_IN Format */
bLength 6
bDescriptorType 36
bDescriptorSubtype 2 (FORMAT_TYPE)
bFormatType 1 (FORMAT_TYPE_I)
bSubslotSize 2
bBitResolution 16
Endpoint Descriptor: /* STD AS ISO IN Endpoint */
bLength 7
bDescriptorType 5
bEndpointAddress 0x80 EP 1 IN
bmAttributes 13
Transfer Type Isochronous
Synch Type Synchronous
Usage Type Data
wMaxPacketSize 0x00c0 1x 192 bytes
bInterval 1
AudioControl Endpoint Descriptor: /* CS AS ISO IN Endpoint */
bLength 8
bDescriptorType 37
bDescriptorSubtype 1 (EP_GENERAL)
bmAttributes 0x00
bmControls 0x00
bLockDelayUnits 0 Undefined
wLockDelay 0
Device Qualifier (for other device speed):
bLength 10
bDescriptorType 6
bcdUSB 2.00
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
bNumConfigurations 1
Device Status: 0x0000
(Bus Powered)