罗技c930e摄像头描述符
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罗技c930e摄像头描述符
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USB描述符存储在设备EEPROM中,枚举时主机向设备发送GetDescriptor请求,设备收到请求后,将描述符信息返回给主机,主机分析返回来数据,判断出设备类型后建立相应数据链接通道
描述符是用来描述自身信息的格式化的数据
Descriptor Hierarchy
This USB camera device uses a Video Interface Collection that includes the VideoControl interface (interface 0) and a single VideoStreaming interface (interface 1). The VideoStreaming interface features two alternate settings. The first alternate setting (0) has zero bandwidth associated with it (implied by the lack of an isochronous endpoint), so switching to this alternate setting frees all allocated bandwidth on the USB for this device. Alternate setting 1 is the operational part of the interface and contains the isochronous endpoint to supply the host with video data.
This figure presents the descriptor hierarchy.
描述符是用来描述自身信息的格式化的数据
Descriptor Hierarchy
This USB camera device uses a Video Interface Collection that includes the VideoControl interface (interface 0) and a single VideoStreaming interface (interface 1). The VideoStreaming interface features two alternate settings. The first alternate setting (0) has zero bandwidth associated with it (implied by the lack of an isochronous endpoint), so switching to this alternate setting frees all allocated bandwidth on the USB for this device. Alternate setting 1 is the operational part of the interface and contains the isochronous endpoint to supply the host with video data.
This figure presents the descriptor hierarchy.
——————/
据VC可找到从属于其的VS
插上摄像头——rmmod uvcvideo——insmod myuvc.ko
仿照lsusb.c写
id_table:VC、VS,打印两次设备描述符,内容同
——————/IAD接口联合描述符,p45
A device must use an Interface Association Descriptor to describe a Video Interface Collection for each device function that requires a VideoControl Interface and one or more VideoStreaming interfaces.
重要成员bFirstinterface、bInterfaceConut
struct usb_host_config——struct usb_interface_assoc_descriptor(老版内核无该项)
——————/接口描述符
C930e的VC仅1种设置,VS有12种设置
——————/UVC规范自定义描述符
了解EU,看厂家数据手册,uvc psec无定义
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