[PLUG] USB ports failed

John Jason Jordan johnxj at gmx.com
Sun Oct 7 01:49:12 UTC 2018


I went to bed last night leaving Handbrake encoding a movie. It often
takes three hours or more for it to complete, so I frequently let it
run overnight. When I got up in the morning Handbrake had failed. A
little checking revealed that the directory it was writing to (an
external USB drive) was no longer mounted or even connected. That
certainly explains why the encode failed, but why did it become
unmounted? 

The computer has two USB 3.0 ports in the back and two more on the
right side. One of the ones in the back holds the receiver for the
wireless mouse (still working), and the other holds a HooToo HT-UE01
3-port USB 3.0 hub with 1 Gigabit ethernet port (not working). The
external drive that Handbrake was writing to (also not working) was
connected to one of the HooToo ports. 

At first it appeared that the whole problem was that the HooToo had
lost contact with the port it was connected to, but a little more
checking revealed that the two ports on the  right side (each containing
a USB flash drive) were also not working.Yet the mouse receiver
continued to work, and furthermore it continued to work when I put it
in any of the other ports.

I had no internet, in spite of the fact that the computer has both
ethernet and wifi, and both were connected. The ethernet was plugged
into the HooToo, so I didn't expect that to be working, but the wifi
should still have been working. To get the net back I moved the
ethernet from the HooToo to the ethernet jack on the computer, which
restored the connection. Then I started searching for how to fix the
mess, but put that aside when it occurred to me that the first priority
was to back up the external drive that Handbrake had been writing to -
because I still didn't know why or how it had become disconnected. (And
I still don't as I write this.) Making the backup took a long time -
not only did I have to get the source drive mounted again, but the NAS
had also become unmounted and my first attempt wrote to the mount point
instead of the NAS. 

Eventually I got back to searching the net for how to fix things. I
discovered the lsusb command, which found all the ports as long as
something was in the port. And after using lsusb all the ports went
back to working, and the HooToo functioned perfectly again as well.

But the big question remains: What the <expletive> happened?

Power problems: My neighborhood is subject to occasional very short
power failures - only a couple seconds, but enough to shut down a
computer. Because of this I run everything off of three rather massive
battery backups. And I mean everything, including all peripherals,
including the drive that Handbrake was writing to, which has its own
external power source.

Physical issues: If something jiggled the connection it could have
disconnected a device, but three of them on different sides of the
computer? Plus this doesn't explain why they continued to fail to work
even after I removed them one at a time and reseated them, or why the
mouse receiver worked in any of the ports, but not the other devices -
that is, until I used lsusb. And there is no explanation for why the
NAS also became unmounted, since it isn't even connected to a USB port.

I've got everything working again and there was no harm done, other
than to what little sanity I have. But I am concerned and curious. Any
comments and suggestions are welcome, and thanks for reading the saga
of my scary day. :)



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