How to fix the USB root hub power management issue in Windows 7
It is a common design for USB ports to be managed by two controllers: one for low speed and full speed (the USB speeds), and one for high speed (the new speed available beginning with USB ). If this is the case, the 3rd root hub is probably from the EHCI controller managing the high speed connections, and the 1st and 2nd root hubs are probably from a pair of OHCI or UHCI controllers managing the low and full speed connections. USB Root Hubs, also known as Universal Serial Bus Root Hubs, serve as viable communication portals for today's technologically enhanced computers and other electronic devices. USB Root Hubs are both physical and virtual installation ports that can be found on your computer. These ports are used for implementing and installing additional hardware files and components to your computer's .
USB allows for a lot of devices to be connected, but they all share the same bandwidth. Some computers will install more than one base port called the root hub to allow you to spread your devices across more than one root hub. Some systems will have separate root hubs, where one is USB 1. The reason is that some 1. Some systems that have USB ports on the front will have those on a separate root hub.
Was this reply helpful? Yes No. Sorry this didn't help. Thanks for your feedback. Will it work fine if I connect let's say an external hard diska printer ,a camera ,or a mobile phone to my laptop through that generic USB hub?
If not what is exactly the purpose of installing that type of hub.? I think it all depends on how much power they all use, USB 3 gives you more power from what i understand, and more speed but I'm not sure what is the maxim power you can how long does it take ringworm to spread. Choose where you want to search below Search Search the Community.
Search the community and support articles Windows Windows 7 Search Community member. This thread is locked. You can follow the question or vote as helpful, but you cannot reply to this thread. I have the same question Nithyananda J.
I would suggest you to follow the link. How satisfied are you with this reply? Thanks for your feedback, it helps us improve the site. In reply to Nithyananda J's post on February 21, Hi ; This does'nt answer my question. To clarify more my question: Will it work fine if I connect let's say an external how to store your scarves diska printer ,a camera ,or a mobile phone to my laptop through that generic USB hub?
In reply to M. Alhadi's post on February 21, Thanks I think it all depends on how much power they all use, USB 3 gives you more power from what i understand, and more speed but I'm not sure what is the maxim power you can consumption. This site in other languages x.
Sep 05, · USB Root Hub. USB allows for a lot of devices to be connected, but they all share the same bandwidth. Some computers will install more than one base port (called the root hub) to allow you to spread your devices across more than one root hub. You can’t tell from how many USB port plugs there are on the computer as each root hub can handle a lot of them. The USB host controller has an embedded hub called the root hub. The ports that are visible at the system's back panel are the ports of the root hub. What I understand from this is that the root hub merely is a point where all usb hubs come toghether. A USB hub is a device that expands a single USB port into several (similar to a power strip), so that more ports are available for connecting devices to a host PC. Devices that can be connected to USB ports on the PC.
While multiple devices that are attached to the same hub are going into selective suspend, one of the devices on the hub can receive a wake request. If this happens before the suspend request has completed, the devices become unstable.
This lets the controllers recover the USB port from its unresponsive condition. To disable and re-enable the USB root, follow these steps:. Restart the computer. After the computer starts, Windows will automatically scan for hardware changes and reinstall all the USB root hubs that you uninstalled. After the computer restarts, check whether the problem is resolved. If this method resolved the problem, you are finished.
If this method did not resolve the problem, go to Method 2. Try restarting the computer. After the computer has restarted, check whether the problem is resolved. If restarting the computer resolved the problem, you are finished. If this method did not resolve the problem, go to Method 3. If the first two methods did not work for you, you can disable the Selective Suspend feature.
Therefore, your computer cannot suspend any USB devices that are connected to it, and the USB devices can continue to use power while connected to the computer. Additionally, the Allow the computer to turn off this device to save power check box does not appear on the Power Management tab for the USB root hub. However, sometimes this feature may not correctly wake up the USB device. Therefore, the USB device is unresponsive when you try to use it.
You might want to disable this feature for server products where power management is not important or required. Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully.
For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:. If the DisableSelectiveSuspend registry entry is present, double-click it. If it is not present, create the entry. To create the entry, follow these steps:. USB devices may stop functioning correctly when multiple devices connected to the same USB hub go into selective suspend Symptoms USB devices attached to the same hub are very slow or completely unresponsive.
Cause While multiple devices that are attached to the same hub are going into selective suspend, one of the devices on the hub can receive a wake request.
Workaround Try these methods to work around this problem. In the Open box, type devmgmt. Device Manager opens. Expand Universal Serial Bus controllers. Note You might have to scroll down the list to find this item. Method 2 Restart the computer Try restarting the computer.
Method 3 Disable Selective Suspend feature If the first two methods did not work for you, you can disable the Selective Suspend feature. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base: How to back up and restore the registry in WindowsTo disable the Selective Suspend feature, follow these steps: Click Start, and then click Run.
Type regedit, and then click OK. Registry Editor opens. On the Edit menu, click Modify. Exit Registry Editor. Need more help? Expand your skills. Get new features first. Was this information helpful? Yes No. Any other feedback? The more you tell us, the more we can help. How can we improve? Send No thanks. Thank you for your feedback! It sounds like it might be helpful to connect you to one of our Office support agents. Contact Support.