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Just curious why this is always on the list for trouble shooting USB devices.
Is it just because how USB works, some kind of tech myth, or just in case there's an actual hardware fault with the USB port?
prasanthv
Posted 2013-11-02T14:12:38.110
Reputation: 231
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Why not?
Firstly, not all USB ports are made the same. Front usb ports are notorious for not supplying enough power for many devices, especially with older/cheaper cases. USB 3.0 may not work for keyboards at boot time for many devices. You might have more than one controller on a system for USB, and that controller may be flakey. In short, it rules out an error with a specific port, its controller, or the physical electrical subsystem that is supporting it.
It is no different from running a minimal system to work out why a motherboard or other device is acting up, and adding things till something fails.
Journeyman Geek
Posted 2013-11-02T14:12:38.110
Reputation: 119 122
Ah damn, it always gets more complicated doesn't it :) Thanks! Know of any good USB analysis tools? – prasanthv – 2013-11-02T14:43:21.780
depends on the OS, and what you're trying to do. this question talks about my efforts in reverse engineering a keyboard to get it to work in linux, and the tools mentioned there are a good start, assuming they still work this question is pretty neat too, assuming you want to focus on keyboards. Finally (maybe I should have said it first), device manager in windows, and lsusb.
– Journeyman Geek – 2013-11-02T14:47:19.477Ah nice the blackwidow, I've bugged around device manager, I should mentioned windows, but was wondering if there was something that focused just on the USB controller. I'll read through the other questions though and post any useful tools I find here. Thanks! – prasanthv – 2013-11-02T14:53:38.090
USBDeview from Nirsoft is nice tool for troubleshooting Windows usb drivers. – week – 2013-11-02T17:25:07.203
USBDView is a good tool, @prasanth. you can use it to see how Windows enumerates USB devices in the registry, see whats active, hubs, drivers in use... – Austin T French – 2013-11-02T17:48:08.547
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Sometimes, Windows will see the same device on a different port as a different device, and reload the drivers for it.
Aric TenEyck
Posted 2013-11-02T14:12:38.110
Reputation: 1 007
Ah ok, I was wondering if that took place, thanks! – prasanthv – 2013-11-02T18:16:09.723
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USB ports may be connected to hubs internally, where power and data transfer must be shared. So it's conceivable that problems may be caused by having other devices on the same physical hub, if you have a device that needs a certain amount of power / transfer rate to function properly.
nmclean
Posted 2013-11-02T14:12:38.110
Reputation: 111
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In addition to the technical answers, there is always the possibility that the device isn't plugged into the USB port properly due to user error. In this case, removing and re-inserting the device could make the user concentrate and insert it properly.
evilsoup
Posted 2013-11-02T14:12:38.110
Reputation: 10 085
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Related: why does plugging into a new USB port often solve USB problems?
– Jan Fabry – 2013-11-02T17:15:01.593