Today I have all USB

Loading Process of USB driver under CE
When a USB device is plugged into the host, there is a check thread in the USB driver module on the host, and the event is set. So after receiving the notification. at this time, the USB driver module only knows that there is a USB device connected, but does not know what class the USB is, so you need to go to the Registry to find the driver that can match the deviceProgram. (Search orderAlgorithm?)
In HKEY_LOCAL_MACHINE \ drivers \ USB \ loadclients, if this device is not connected for the first time, (yes ?) There is a note for the device driver. If this is the first time, the USB driver module fails to be searched, a dialog box is displayed, asking the user to enter the DLL name of the device driver. The USB driver then loads the DLL and calls the usbinstalldriver function. This is only installation, but also attach.
After the USB driver loads the driver DLL, it calls the USB deviceattach function of the driver. This function mainly implements the following tasks: the driver determines whether the device can be controlled. If yes, return true and accept control. If no, return false to continue searching for other drivers.

When the device is disconnected from the host, the USB driver module calls the registered callback function. Then the callback function can choose to call usbuninstalldriver (if you do not choose to call this function .... When can I choose to call it ). The USB driver never directly calls the usbuninstalldriver function. Usbuninstalldriver does the following: Delete the registry keys created in all usbinstalldriver functions and release other resources occupied by all drivers.

Of course, the USB driver here refers to the client driver.

The Universal Serial Bus (USB) host mass storage client also implements three functions required by the client DRIVER: the USB Host mass storage client driver is implemented as a USB client driver. it exposes the usbinstalldriver, usbdeviceattach, and usbuninstalldriver entry points to support plug and play functionality.