Device State Management

Managing a USB device includes accounting for hotplugging, system power management (checkpoint and resume), and device power management. All client drivers should implement the basic state machine shown in the following figure. For more information, see /usr/include/sys/usb/usbai.h.

Figure 20-4  USB Device State Machine

This state machine and its four states can be augmented with driver-specific states. Device states 0x80 to 0xff can be defined and used only by client drivers.