How to "restart/repair" an USB port?

Question

My laptop has two USB ports, but one is broken, so I use a USB hub in the other good USB port. In that USB hub, I use a mouse and keyboard. Suddenly, that USB port doesn't detect the mouse and the keyboard (even with the light of the hub is on), and the only solution that I found is restarting the laptop. But just some minutes and the keyboard and mouse goes undetected again...

Is there some method, software, etc. to "restart/repair" the USB port without restarting the PC?

Solution 1

None of the answers quite answer the title question.

How to “restart/repair” a USB port?

There are three ways to "restart" a particular USB port:

1. Reboot the computer. Or ...
2. Unplug, then re-plug, the physical device connected to the port. Or ...
3. Disable, then re-enable, the USB Root Hub device that the port is attached to.

In Windows you'd do (3) through the Device Manager or via the devcon.exe utility.

The reason these are the only methods is due to the USB handshaking protocol, which is initiated by the USB device when it's plugged in, not by the controller. This causes problems like being unable to remount a USB flash drive after you've Safely Removed it. But cycling the USB Root Hub device causes all the devices attached to that hub to reinitialize themselves. (The unfortunate side effect is that it causes all devices attached to that hub to reinitialize themselves, which could be problematic if you have other devices on that hub which are in use.)

Solution 2

You should look at NIRSOFT's USB Device view (http://www.nirsoft.net/utils/usb_devices_view.html). I have used this to fix a system that had a disconnected U3 USB drive still mounted preventing anything else in the port being recognized.

Solution 3

I had issues with Windows 7 dropping the USB mouse driver and reinstalling the mouse driver (most of the time) which was annoying as hell.

I tried all kinds of things to fix the problem, driver updates, clean boots, tech support phone calls, Internet software voodoo, but in the end I only had to reset my USB ports.

I did this by turning the computer off, unplugging all USB devices, removing the laptop battery and AC power supply, and finally holding down the power button for 30 seconds.

This fixed a problem that I must have spent at least 20 hours trying to fix; give it a try.

Solution 4

If you have no power supply added to the USB hub, check if that helps. Maybe the laptop doesn't have not enough power on the USB; some older laptops didn't have not the full 500 mA.

Solution 5

Can you check your event viewer for any obvious errors in the application or system logs?

I don't know what the problem is at this point, but you should inspect the drivers installed. Are they Microsoft default input drivers or custom drivers? You might need to reinstall the drivers. It could be possible that the instance of the drivers is failing.

Also try inspecting the drivers after plugging in the device. You might see a resource conflict or some other warning in Device Manager.

Since the problem is occurring for two different devices, I think it's less likely a hardware failure on the mouse or keyboard.

The failure is definitely on your laptop.

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Comments

[Click Ok]

Interesting! How I can check that voltage?

[Paul Lammertsma]

Powering a mouse and a keyboard via the USB port should not be a problem. I really wouldn't worry about that.

[Thomas]

Some computers show the voltage in their driver settings. Regarding the power consumption - or the problem - try finding the combination that brings trouble by using only one of the components, e.g. only mouse without the hub and the keyboard and if that works use only the keyboard and so on. Alternatively you can check if you have a power supply that fits to the hub, e.g. on my hub I the disk did not work and I found a 5V power supply that had the same +- combination and plug and now it works. Again: My old Dell Laptop produced only 300-400 mA.

[pratnala]

This is THE answer

[nixda]

Basically the same answer as quack quixote already gave

[Simon]

is it possible to disable a hub that is running your keyboard / mouse (internal or external) thus making it impossible to restart the hub again? I guess not otherwise somebody would have said so by now....... or maybe that can't with no keyboard?...

[user276648]

Unplug then replug is the best solution, if possible. Restarting the computer as well as disabling then enabling the USB device may not fix all the problems, as the device stays powered the whole time.

[Rowan Hawkins]

It is not a lack of voltage, but instead one of current. Think of it like a pipe -- the Voltage is the size of the pipe and Current is how much water you have. All USB port devices connect to a 5v pipe but only has 500ma of water, if all of the devices don't get enough water(electricity) they don't work. Each device uses a certain amount of the 500ma available if you over load the circuit then all of the devices can behave wonkey. the hub itself also uses part of that 500ma so powering it powers the devices you attach to it.

[Rowan Hawkins]

Nirsoft is good at removing the drivers for devices that are not attached as well. This lets you reset and then reattach the device.

[setec]

It may help to use externally powered USB hub, especially if powering hungry devices like WiFi modems or Storage drives.