[GTALUG] USB power reporting Type-c super speed skirmish and libpartd error

D. Hugh Redelmeier hugh at mimosa.com
Wed Sep 23 15:52:21 EDT 2020


| From: Russell Reiter via talk <talk at gtalug.org>

|  I power off, unplug
| the power cable and press and hold the start button for a few seconds to
| see if I can dissipate any lingering bus voltage. I don't have a "manual"
| troubleshooting direction to do that, but things did start acting better
| when I started to do it. This was a practice I used to do diligently in the
| 90's, from before switched power supplies, but I never needed to do it much
| after 2000.

At first I thought you meant "switching power supplies", but they were
introduced much earlier.

Now I'm guessing you mean power supplies that are switched on and off
by the motherboard, rather than by a direct power supply switch.  I
guess that came in with the PS/2.  (A lot of PC power supplies also
have direct switches but those switches tend not to get used.)

If you turn off a PS through the motherboard, there is still some
power available.  I infer it is used for

- turning on the computer via a firmware timer (I often see this
  option in a firmware setup page but have never used it)

- USB charging even when the computer is off

- wake-on-thing (LAN, Keyboard, mouse, whaterver)

- lights-out updates

If you turn off the direct power supply switch, none of that will
work.  Unplugging the power supply from the wall should have the same
effect.

Anyway, your procedure should really reset things in a way that might
not happen otherwise.


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