Windows 8 and 8.1 Forums


Power Options - Add or Remove "USB 3 Link Power Mangement"

  1. #1
    Power Options - Add or Remove "USB 3 Link Power Mangement"

    Power Options - Add or Remove "USB 3 Link Power Mangement"
    How to Add or Remove "USB 3 Link Power Mangement" in Power Options in Windows 8
    Published by Brink is online now
    17 Jul 2014
    Default Power Options - Add or Remove "USB 3 Link Power Mangement"

    Published by


    Brink's Avatar
    Administrator

    Join Date: Jul 2009
    Posts: 22,577

    How to Add or Remove "USB 3 Link Power Mangement" in Power Options in Windows 8


    information   Information
    What is a link

    A USB connection between two USB ports. For example, between your PC and a USB 3.0 device.

    • The downstream port (DS port) of a host or a hub.
    • The upstream port (US port) of an attached device or hub.

    A link is a pair of DS and US ports; the ports are known as link partners. Each port has two layers. The physical layer transmits or receives sequences of bytes or other control signals. The logical layer manages the physical layer and ensures smooth flow of information between the link partners. The logical layer is also responsible for any buffering that might be required for the information flow.


    U states

    As per the USB 2.0 specification, a link enters a low power state (consuming less power than the working state) only when the downstream device enters the suspended state through the Selective Suspend mechanism. The USB 3.0 specification decouples link power states from device power states. The specification defines the LPM feature (see Section C.1 in the specification) that refers to power management of physical and logical layers of a pair of ports that constitute a link. The specification defines four link power states known as U states, from U0 to U3. An active link is in state U0.

    After remaining idle for a certain period of time, link partners progressively enter U1 (standby with fast exit) and then U2 (standby with slower exit). After they are idle for sufficient time, software initiates the transition to U3 by sending a command to the DS port link partner.

    The steps that are required by software, to send the link to U3, are identical to the steps required for USB 2.0 Selective suspend. The device must enter the suspended state when the link enters U3. As a result, the device is subject to similar restrictions as with USB 2.0 Selective Suspend. To overcome those limitations, the USB 3.0 specification defines U1 and U2 states.


    Advantages of U1 and U2

    U1 and U2 states are designed to complement Selective Suspend, which can lead to significant power savings. After the software configures the link partners for U1 or U2 transition, the hardware enters the states autonomously without any software intervention. The exit times from U1 and U2 are really fast (from microseconds to a few milliseconds) and have less of an impact on the performance of the devices. This allows for much better power management where links can enter and exit these states even when the device is in use.

    For example, a device with isochronous endpoints can put the link to U1 or U2 between service intervals. To save some power, when the device is idle, it can send its upstream link to those states even before Selective Suspend gets invoked. There are no restrictions on how much power the device can draw when the link is in U1 or U2. A device could remain fully powered when the link is in U1 or U2. Therefore, unlike Selective Suspend, a device can send its link to U1 or U2 without losing any capabilities.


    For more detailed information, see:



    This tutorial will show you how to add or remove the "USB 3 Link Power Mangement" setting under USB settings in Power Options for all users in Windows 8 and 8.1.

    This setting specifies a power management policy below to use for USB 3 links when they are idle.

    • Off = Do not enable the U1 U2 states.
    • Minimum power savings = Enable the U1 U2 states, but choose conservative timeout values to optimize for performance.
    • Moderate power savings (default) = Enable the U1 U2 states, and choose optimal timeout values to balance power and performance.
    • Maximum power savings. = Enable the U1 U2 states, and choose aggressive timeout values to optimize for power.


    You must be signed in as an administrator to be able to do the steps in this tutorial.

    Note   Note
    This could be handy if you wanted to set this how you wanted, then remove the setting to prevent other users from being able to change it in Power Options.


    EXAMPLE: "USB 3 Link Power Mangement" in Power Options

    Name:  USB_3_Link_Power_Mangement.png
Views: 14080
Size:  35.1 KB



    Here's How:

    Note   Note
    The .reg files below are for the registry key and value below.

    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Power\PowerSettings\2a737441-1930-4402-8d77-b2bebba308a3\d4e98f31-5ffe-4ce1-be31-1b38b384c009

    Attributes DWORD

    1 = Remove
    2 = Add



    1. Do step 2 or 3 below for what you would like to do.


    2. To Remove "USB 3 Link Power Mangement" from Power Options
    NOTE: This is the default setting.

    A) Click/tap on the Download button below to download the file below, and go to step 4 below.

    Remove_USB_3_Link_Power_Mangement.reg

    download

    3. To Add "USB 3 Link Power Mangement" to Power Options

    A) Click/tap on the Download button below to download the file below, and go to step 4 below.

    Add_USB_3_Link_Power_Mangement.reg

    download

    4. Save the .reg file to your desktop.

    5. Double click/tap on the downloaded .reg file to merge it.

    6. If prompted, click/tap on Run, Yes (UAC), Yes, and OK to approve the merge.

    7. When finished, you can delete the downloaded .reg file if you like.



    That's it,
    Shawn


    Related Tutorials



  2. #1


    Hi Shawn,

    My system is Windows 7 with NEC USB 3.0 Host.
    But, no link power management added following the steps.
    Is it only for Window 8?

    416

      My System SpecsSystem Spec

  3. #2


    Posts : 22,577
    64-bit Windows 10


    Hello Taipei, and welcome to Eight Forums.

    Yep, it's only available in Windows 8 and 8.1.
      My System SpecsSystem Spec

  4. #3


    Posts : 511
    Windows 10 Pro 64 bit


    Thanks Brink. I added the .reg file and set it to off. I hope it stops my WD USB 3 external HD from going to sleep. I have tried all the other tricks. None worked so far. What's strange is I have 2, one sleeps the other does not.
      My System SpecsSystem Spec

Power Options - Add or Remove "USB 3 Link Power Mangement"
Related Threads
How to Add or Remove "Minimum processor state" and "Maximum processor state" in Power Options in Windows The Minimum processor state is the minimum performance percentage your CPU will automatically decrease to save energy and battery life when there is little CPU demand by the system. You...
How to Add or Remove "When sharing media" in Power Options in Windows The When sharing media setting in Power Options will let users configure power settings for when devices and computers are playing media from your computer to either allow the computer to sleep, prevent idling to sleep, or...
How to Add or Remove Desktop Background "Slide Show" in Power Options in Windows You can have a slide show (a rotating series of pictures) as your desktop background. You can use your own pictures or pictures that Windows provides as part of a theme. The Slide show power option allows...
How to Add or Remove "System cooling policy" in Power Options in Windows The System cooling policy power option allows you to specify the cooling mode you want to use for your system. Active = Increase fan speed to cool first, and only slow the processor to cool as a last resort. Passive...
How to Add or Remove PCIe "Link State Power Management" in Power Options in Windows The Link State Power Management is a part of PCI Express Active State Power Management (ASPM). The link State of a PCIe Device is converted from L0 (on) to L1 (off) when the link is not transferring data. The...
How to Add or Remove "Turn off hard disk after" in Power Options in Windows The "Turn off hard disk after" power option setting lets users set to have hard disks power down after a specified time of inactivity is detected. When you set to turn off hard disks after idle, there will be a...
How to Add or Remove "Allow Away Mode Policy" in Power Options in Windows Away Mode in Windows is similar to Sleep and Hibernate Mode, it turns off the power of most equipment to save energy and can be fast woken up. Away Mode is designed to enable media PC scenarios that include background...
Eight Forums Android App Eight Forums IOS App Follow us on Facebook