Whitepaper on Link Power Management (LPM) in USB 3.0 Hardware

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 USB 3.0 Link Power Management (LPM) in conjunction with selective suspend. It also provides information about…

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What to Try When Your USB Device is an "Unknown Device"

Here are some common causes and solutions for users facing an “Unknown Device” problem.  This post is a follow-up to Why is my USB device not detected or comes up as “Unknown Device”?. 1) The USB device is “hung”. The USB device may have encountered an internal error and simply stopped functioning.  The device will…

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What’s new in the Windows Developer Preview for USB?

There is a lot of news coming out of the BUILD conference this week.  In the realm of USB, we’ve released preliminary documentation of the USB 3.0 core drivers.  Check out new architectural diagrams and client driver interfaces! While we’re at at it, the BUILD conference is also bringing you several USB-related sessions and pre-recorded…

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USB Mass Storage and Compliance

Hi, I’m Ram Valliyappan and I am a Program Manager on the Windows team responsible for USB mass storage drivers. We often get asked the following questions: · What is USB-IF compliance for USB mass storage devices? · What is SCSI compliance for USB mass storage devices? · Why is compliance for USB mass storage…

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Demystifying USB Selective Suspend

Hi, I am Vivek Gupta, a software developer on the USB team. In this blog, I am going to talk about why USB selective suspend mechanism is needed and important, and how to implement it correctly in devices and drivers. I will start by discussing the concept of run-time power management in devices, discuss the…

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Several inbox USB drivers may not get updated on upgrade from Win7 RTM to Win7 SP1

When upgrading from Windows 7 RTM to SP1 on a clean Windows 7 RTM build, binaries such as usbport.sys, usbehci.sys and winusb.sys may not get updated. Machines that have INF files from OEMs to install USB drivers with a custom description will not get affected. This issue doesn’t exist if you use a slipstream version…

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How to Map Ports for Add-in Host Controllers

My name is Jane Lawrence, and in this blog post, Philip Ries and I will describe the details of the Busport-0048 Windows Logo Kit (WLK) requirement that has been in effect since Dec 1, 2010. The Busport-0048 requirement states “xHCI add-in cards must map USB 3.0 and USB 2.0 ports consistently”. The requirement targets manufacturers…

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How to Generate a Container ID for a USB Device – Part 2

Hi, I’m Kristina Hotz, a Program Manager on the USB team.  In December, I wrote a blog post – How to Generate a Container ID for a USB Device.  A natural follow-up question is, as a device developer, When should I supply a container ID and how should I supply that ID so that Windows…

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Whitepaper Published! Learn about Loading a UASP Storage Driver as the Class Driver for an xHCI Controller’s USB Driver Stack

Hi, I’m Kristina Hotz, a Program Manager on the USB Team.  In this post, I’d like to promote a new whitepaper on the Windows Hardware Developer Central Website.  The whitepaper provides information about loading a USB Attached SCSI Protocol (UASP) storage driver as the class driver on a USB driver stack for an Extensible Host…

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