UAC麦克风类特定音频控制接口描述符

UAC的类特定音频控制接口描述符又叫类特定音频控制接口头描述符，包含了UAC音频控制各终端，单元的描述符信息。
在UAC规范中，其包含的描述符有：

关于类特定音频控制接口描述符可详见本站：http://www.usbzh.com/article/detail-222.html

由于该UAC麦克风是基于UAC1.0开发的，所以其类特定音频控制接口描述符的参数如下：

#define DECLARE_UAC_AC_HEADER_DESCRIPTOR(n)\ struct uac1_ac_header_descriptor_## n {\
    __u8 bLength;\
    __u8 bDescriptorType;\
    __u8 bDescriptorSubtype;\
    __le16 bcdADC;\
    __le16 wTotalLength;\
    __u8 bInCollection;\
    __u8 baInterfaceNr[n];\
}
__attribute__((packed))

/* B.3.2  Class-Specific AC Interface Descriptor */
static struct uac1_ac_header_descriptor_1 uac1_header_desc = {
    .bLength = UAC_DT_AC_HEADER_LENGTH,
    .bDescriptorType = USB_DT_CS_INTERFACE,
    .bDescriptorSubtype = UAC_HEADER,
    .bcdADC = __constant_cpu_to_le16(0x0100),
    .wTotalLength = __constant_cpu_to_le16(UAC_DT_TOTAL_LENGTH),
    .bInCollection = F_AUDIO_NUM_INTERFACES,
    .baInterfaceNr = { /* Interface number of the first AudioStream interface */
        [0] = 1,
    }
};

使用Free Device Monitoring Studio 对该设备的类特定音频控制接口描述符抓取显示如下：

• descriptors[2] = “Class-Specific Interface Descriptor”
• bLength = 9
• bDescriptorType = CS_INTERFACE (36)
• bDescriptorSubtype = 1
• ac_interface =
• header =
• bcdADC = 256
• bCategory = 39
• wTotalLength = 256
• controls =
• header =
• LatencyControl = 1
• Reserved = 0
• bmControls = 00000001