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描述符存儲在設備EEPROM中,枚舉時主機向設備發送GetDescriptor請求,設備收到請求后,將描述符信息返回給主機,主機分析返回來數據,判斷出設備類型后建立相應數據鏈接通道
描述符是用來描述自身信息的格式化的數據
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.
描述符是用來描述自身信息的格式化的數據
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.
——————/
據VC可找到從屬于其的VS
插上攝像頭——rmmod uvcvideo——insmod myuvc.ko
仿照lsusb.c寫
id_table:VC、VS,打印兩次設備描述符,內容同
——————/IAD接口聯合描述符,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.
重要成員bFirstinterface、bInterfaceConut
struct usb_host_config——struct usb_interface_assoc_descriptor(老版內核無該項)
——————/接口描述符
C930e的VC僅1種設置,VS有12種設置
——————/UVC規范自定義描述符
了解EU,看廠家數據手冊,uvc psec無定義
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