About This Download

This paper provides information about certain limitations of the Universal Serial Bus (USB 2.0) Selective Suspend mechanism. It provides guidelines for independent hardware vendors (IHVs) and original equipment manufacturers (OEMs) to implement power management for USB devices by using Link Power Management (LPM) in conjunction with Selective Suspend. It also provides information about common pitfalls in LPM implementation in USB controllers, hubs, and devices.

This paper assumes that the reader is familiar with:

• The official USB 3.0 Specification.
• The USB Selective Suspend mechanism.
  The mechanism is described in the blog post, Demystifying USB Selective Suspend.

This information applies to the following operating systems:

       Windows 8

Included in this white paper:

      Limitations of USB 2.0 Mechanism
      USB 3.0 LPM Mechanism
      U1 and U2 Transitions
      Common Hardware Problems with U1 or U2 Implementation