Meanwhile there is support for a lot of USB devices. Unfortunately, scanners are not on the list. The main reason for this is that there is no real standard for them and every scanner needs its very own, special driver. Drivers from IBM are going to be written for device classes where it is possible to support many devices with a single driver.As far as scanners are concerned we may be lucky in the future as STi has announced to re-vamp their drivers and look into USB.
The base USB device driver only implements a common USB stack. Other device-specific drivers use it communicate with the devices.