About : 配置描述表 !

一般再得到配置描述表时，总是调用两次USB_CONFIGURATION_DESCRIPTOR_TYPE 的 URB ， 难道仅仅是因为
想得到具体的 Size 吗（第一次）？

应该是这样，2000ddk的说明很清楚！
The UsbBuildGetDescriptorRequest routine builds the necessary request. The bus driver returns the configuration descriptor in a USB_CONFIGURATION_DESCRIPTOR structure. This structure specifies the total length of configuration information in its wTotalLength member.

A device may support multiple configurations, numbered starting at zero. It reports the number of configurations it supports in its device descriptor. See USB Device Descriptors for details.

尺寸并不固定！

Received !
Thanks a lot !