Sometimes Ubuntu doesn't connect to my external USB drive

Ernest Doub hideserted at gmail.com
Fri Jul 29 18:40:56 UTC 2011


On Fri, Jul 29, 2011 at 9:11 AM, Johnny Rosenberg <gurus.knugum at gmail.com>wrote:

> 2011/7/15 NoOp <glgxg at sbcglobal.net>:
> > On 07/14/2011 04:59 PM, Johnny Rosenberg wrote:
> > ...
> >> Jul 15 01:56:30 EasyNote-MX66 kernel: [56274.949093] usb 1-2: new high
> >> speed USB device using ehci_hcd and address 89
> >> Jul 15 01:56:30 EasyNote-MX66 kernel: [56275.052409] hub 1-0:1.0:
> >> unable to enumerate USB device on port 2
> >>
> >> So it seems like it's at least trying, but failing for some reason…
> > ...
> > After a little googling, most of the 'unable to enumerate' errors seem
> > to come from hardware issues (low power/dirty usb ports). Just for the
> > heck of it, can you move it to another usb port, preferably a back usb
> > port if it is on a desktop?
>
> It's a laptop. It doesn't matter which USB port I use.
>
> > Reason for asking is that usb ports on the
> > front of a desktop typically are wired extensions of the motherboard usb
> > ports (the ones that are connected to the back) & can pick up rf
> > interference and experience low power. Might also be a faulty cable.
>
> Checked with different cables.
>
> > You could check the power:
> > http://pinouts.ru/Slots/USB_pinout.shtml
> >
> > Also, in one bug report several users seemed to resolve by cleaning the
> > usb contacts. Shot in the dark, but worth trying.
> >
> > Other possibilities:
> >
> > 1. Is your bios up to date? Older versions of bios may have difficulty
> > with newer high speed usb 2.0 devices.
>
> I just visited their home page and I couldn't even find my laptop
> there (I found a lot of other ones though), so I don't know if there
> is an update somewhere…
>
> > 2. If you think you can rule out hardware/cables/power/RFinterference,
> > then you might try backing down to an older kernel, or trying a newer
> > kernel to see if there is any change. Also try searching:
> > <
> https://launchpad.net/+search?field.text=unable+to+enumerate+USB+device+on+port
> >
>
>
> Thanks for all tips and advice.
>
> In this case the problem seems to be something else though: I have a
> printer (HP Color Laserjet CM1312 MFP) and I use it with two computers
> using a USB switch (two computers to one USB device). It's a passive
> switch and there are two push buttons: On for connecting the printer
> to my computer, and one for connecting it to my wife's. She has no
> problems with it whatsoever, but when ”my” push button is pressed,
> there seems to be some problems on most of the other USB ports, except
> the one to which I connected my keyboard and mouse (I never use my
> laptop's built in crap).
>
> So I just pressed pressed the ”connect my wife's computer to the
> printer” button instead and my external drive is now found without any
> problems each time.
>
> The strange thing is that when I connect the printer directly to the
> USB port the problem does not occur, so I wonder how a passive switch
> can cause problems like this…
>
>
> Kind regards
>
> Johnny Rosenberg
> ジョニー・ローゼンバーグ
>
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You may have a bad switch.
Try changing the connections so your wifes computer is on the button you
push to select yours and visa-versa.
If the problem changes you know the switch is bad.  If it doesn't then you
have eliminated that component as a contributor to the problem.
Basic black box troubleshooting.



-- 
When Government fears the people there is Liberty.
When People fear the Government there is Tyranny.
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