Hi!

Did anyone managed to get active extension cables work with Linux? I do
have one to achieve long distance between the workplace and the computer
itself (about 10 meters). It's mostly a cable with a hub attached to it,
though only the electric part the hub - it repeats the signals, but
doesn't behave as an USB device, it is completely transparent. The
problem is that any device connected to the cable isn't identified at
powerup, only when I plug the cable out and back in after power up.  No
errors are printed, no warnings. Just as if the cable wasn't plugged in.
This is the same when the cable is plugged into a root hub or a hub
connected to the root hub. After unplugging and replugging the cable
after powerup everything works fine until the hub which the cable is
connected to is unplugged from the root hub. Happens both with UHCI and
OHCI. Reportedly doesn't happen with Windows.

If the above paragraph is too confusing, here is a graphical description
of the problem:

1) PC switched off, everything fine (off)

power -X- PC --- hub --- active cable --- mouse
 ok       off    off     off              off

2) Switch PC on, hub does enumerate, the lights go on on it, but that's
all, no plug events on the hub:

power --- PC --- hub --- active cable --- mouse
 ok       on     on      ???              doesn't work

3) Unplug the cable:

power --- pc --- hub -X- active cable --- mouse
 ok       on     on      off              off

4) Replug the cable, plug event appears, mouse works:

power --- PC --- hub --- active cable --- mouse
 ok       on     on      on               ok

5) Unplug the hub, everything as expected:

power --- pc -X- hub --- active cable --- mouse
 ok       on     off     off              off

6) Plug in the hub and you're in state 2 again.

power --- PC --- hub --- active cable --- mouse
 ok       on     on      ???              doesn't work

Any ideas why this does happen? Any ideas how to work it around?
Unfortunately I can't replace the active extension cable with either a
passive one or a hub, I'd do it a long time ago, but it's already built
into the wall ...

-- 
Vojtech Pavlik
SuSE Labs

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