I have a Lenovo X1 Carbon running Windows 7. It has 1 USB 2.0 and 1 USB 3.0 port. In the office I have the official Lenovo USB 3.0 "dock" which has a 5 port USB 3.0 hub, Display Link video and Ethernet. So this uses the USB 3.0 port on the laptop for the upstream connection.

When I plug a mouse into the Lenovo hub it works fine. The mouse also works when connected directly to the USB 3.0 port.

At home I just bought a laptop stand/riser which happened to include a little 4 port hub which is quite handy (I might buy another "dock" type unit later though). Plugging it into either of the laptop's USB ports and it's detected fine with no drivers required I think just as "Generic USB hub". Plugging in a Dell keyboard into the hub and it works just fine.

The problem comes with the mouse. It's an old MS Intellimouse. If I plug it into the 4 port USB hub it's simply not detected and doesn't power up. Nor is it detected when I plug it into the 2 ports built into the keyboard. This latter configuration definitely worked in Windows XP on my old machine (totally different Dell laptop). In that case though the keyboard was plugged into the Dell's docking station. There was no separate hub in between but the keyboard should be considered a hub.

I've seen this before where USB mice only seem to work on certain USB ports on both desktops and laptops. I presume this may be because some ports may be on downstream hubs but I don't understand why a mouse wouldn't work just because it's on a hub. Sure it might not be optimum and might be "laggy" but it should still work.

Any ideas? Writing this I was thinking of just trying a Linux live CD to prove it's not hardware, but I'm somewhat sure it isn't anyway. Googling didn't turn up much at all. I was surprised at that since I've seen similar things before. I thought it would be a common gripe.

Thanks

Does the home hub have it's own power supply?

(an older peripheral like that mouse might advertise too high of a current draw, causing the system to refuse service to it on a bus-powered hub)

It's not powered, no (and the Lenovo dock obviously is). It does have a DC connection so assuming I have the right DC plug I can power it at least temporarily.

With just those two devices though, it shouldn't really matter should it? I doubt the mouse is using that much power.

How is it different if the hub is in line? I assume it has to allocate 1 unit of power (100mA) of its own leaving 400mA for the keyboard and mouse. Even with just the mouse it doesn't work either.

I'll give your suggestion a go. If I power the hub should it then report differently?

If you power the hub, I fully expect the mouse to work.

With an unpowered ("bus powered") hub, it's more of a crapshoot: each device, including the hub, advertises it's power needs to the host, and the total has to be small enough to accommodate whatever the root hub (in the PC) advertises that it is capable of (normally 500mA).

It is quite possible that the hub, and/or the mouse, advertise a higher number than they really need. Edit: And the hub itself will normally advertise different values when self-powered than when bus-powered.

OK. Unfortunately the socket used isn't what I thought so I don't have any suitable adapters to power it.

However, I did try another unpowered USB hub I had and the mouse and keyboard work just fine when both are directly running off it. However the mouse does not work when connected to the keyboard's hub (which in turn connects to the second unpowered hub).

Are there any Windows diagnostic tools that might tell me what's going on here?

Dunno. But if you boot Linux and have the usbutils package installed, then you can find out pretty much everything with: lsusb -vvv

Well for whatever reason it seems to be working fine now.

I have both devices plugged into the unpowered hub and plugging and unplugging the hub at the upstream point i.e. at the laptop seems to work fine.

Puzzled. I'm am 100% positive this didn't not work last night!

Loose connector?

Device Manager, USB and find each HUB. In properties for each hub is a power tab showing available and in use power over the bus. Should show how much the mouse is asking for and receiving, even in an underpowered situation.

Maybe but could only have been on the mouse since the keyboard was working via the hub and I plugged and unplugged it a few times.

I'll have a look at that. There's that devices by connection option which probably makes it quite clear.

I did use it all day yesterday and unplugged it a few times. Every time I plugged it in, it worked fine. So beats me what I did wrong initially. The mouse still doesn't work when plugged in to the keyboard though but that's fine.