Sometimes Ubuntu doesn't connect to my external USB drive

Johnny Rosenberg gurus.knugum at gmail.com
Fri Jul 29 18:47:49 UTC 2011


2011/7/29 Ernest Doub <hideserted at gmail.com>:
>
>
> 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.

I know it's basic, and I have done that already. There were no
difference or very little difference. Just seems like my computer is
more sensitive than hers… Still, it works if I connect the printer
directly to my computer.

On the other hand, I shouldn't say that I am too sure about this,
because it was some time ago now that I tested this more thoroughly
and I might have forgotten the details… I guess I need to test it
again before saying anything more about this…



Kind regards

Johnny Rosenberg
ジョニー・ローゼンバーグ




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