Re: usb drive nolonger registers on one pc, still registers on another

[Camaleón <noelamac@gmail.com>]

On Fri, 17 Dec 2010 15:07:53 -0500, Thomas H. George wrote:

> On Fri, Dec 17, 2010 at 08:24:01AM +0000, Camaleón wrote:

>> Even if you boot up with just the USB hard disk attached? :-?
>> 
> Found that if I power down the computer - not just reboot - and connect
> the USB drive its drive light begins to flash immediately.  Then when
> the computer is powered up as bios is loaded the drive is recognized at
> the bnttom of the list of hard drives available for the boot sequence
> and its drive light comes on steadily.  The boot sequence continues
> normally and when complete the USB drive can be mounted but only by
> root!
> 
> This does not solve the hot plug problem!

Nope, not at all :-(
 
> The moment the USB drive is unmounted it returns to the previous state -
> flashing steadily while the "unable to enumerate USB device on port 2"
> message scrolls by.
> 
> I regularly connect my Sansa MP3/MP4 player to this same usb port and
> mount it as user tom.  Again there is a message "unable to enumerate USB
> device on port 2" but there is no problem in continuing.  Here is the
> tail of dmesg:

(...)

Okay, it seems to be working fine. Is your USB hard disk being powered 
externally or it uses the USB's own voltage?

>> > Tried rmmod ehci_hcd which removed the module.  This did not help,
>> > same result as above.
>> 
>> "Same" message cannot be ;-)
>> 
>> If the high speed USB module was removed, "ehci_hdc" should not be
>> present in your "dmesg" log when plugging the drive (resend the log
>> again, once you unload "ehci_hcd" module).
> 
> You are correct.  After rmmod ehci_hcd the tail of dmesg is
> 
> [ 1441.408024] hub 2-0:1.0: unable to enumerate USB device on port 2 [
> 1441.816519] hub 2-0:1.0: unable to enumerate USB device on port 2 [
> 1442.240023] hub 2-0:1.0: unable to enumerate USB device on port 2 [
> 1442.824520] usb 2-2: new full speed USB device using ohci_hcd and
> address 41 [ 1442.888534] hub 2-0:1.0: unable to enumerate USB device on
> port 2 [ 1443.136518] hub 2-0:1.0: unable to enumerate USB device on
> port 2 [ 1443.544520] hub 2-0:1.0: unable to enumerate USB device on
> port 2 [ 1443.960519] hub 2-0:1.0: unable to enumerate USB device on
> port 2 [ 1444.384020] hub 2-0:1.0: unable to enumerate USB device on
> port 2 [ 1444.792017] hub 2-0:1.0: unable to enumerate USB device on
> port 2
>> 
> Note these messages would scroll by rapidly as addresses 5 through 127
> would be tried repeatedly

There is still one more thing I would try: completely unload and reload 
all of the USB modules (modprobe -r ehci_hdc; modprobe -r ohci_hdc; 
modprobe ehci_hdc; modprobe ohci_hdc) and then, switch on your USB drive. 
If none of the above helps, I would fill a bug.

Greetings,

-- 
Camaleón