[CentOS] How to reset the USB subsystem?

Fri Jan 15 19:21:54 UTC 2021
Jon LaBadie <jcu at labadie.us>

On Thu, Jan 14, 2021 at 12:18:10PM -0500, Fred wrote:
>from a non-expert (me):
>possibly figure out what happens when the device is plugged/unplugged and
>doing that by hand. if you can find the udev file(s) that manage the
>port(s) that get hung you may be able to figure out what those steps would
>or you could try, when hung, plugging it into a different USB port... some
>motherboards have multiple USB controllers, so even if one gets wedged
>tight, the other one(s) shouldn't be.
>Good Luck!
>On Thu, Jan 14, 2021 at 11:22 AM Frank Bures <listfrank1 at gmail.com> wrote:
>> Hi,
>> my USB connected printer goes into deep space from time to time probably
>> due to a HW problem on the MoBo.
>> Is there a way how to reset the USB subsystem the same way one can restart
>> networking or X without the necessity to reboot?

Couple of cable ideas that may be of interest.  I got all of these
from Amazon.

In my new car there is only one usb port to connect data deviced to.

When I used my micro thumb drive to play music the car often "lost"
the drive and it had to be pulled and reinserted.  Not easy with the
micro drives.

A second problem was using the one port for music source or plugging
in my phone for Android Auto.  The cars usb system would not deal with
a hub of any sort.  Thus the nice credit card sized 4 port hub with
individual on/off buttons for each port did not work.

The lost thumb drive was solved with a cable having an on/off switch.
Think of it as a 15 inch usb extension cable (M -> F) with a switch
in the middle.

Both problems were solved with a USB printer A/B switch.  This is not
a hub, but a switch intended to let you print to either of 2 different
printers from a computer having a single USB port.  In my case the
music thumb drive and the phone are the "printers".

Jon H. LaBadie                  jcu at labadie.us