[Nut-upsuser] Tripp-Lite USB constantlly disconnecting.

Charles Lepple clepple at gmail.com
Sat Sep 20 12:47:43 UTC 2014

On Sep 19, 2014, at 7:48 PM, Shade Alabsa <shade34321 at gmail.com> wrote:

> So I was wondering does NUT do anything which would cause the USB to disconnect?

Not intentionally, no. The reconnection code is meant to clean up after these disconnection events, but it is something that isn't expected all that frequently.

> I didn't think so and I couldn't find anything yet it's quite possible I missed it. I've tested this with CentOS 6.5 and Fedora 20. With CentOS we were using nut-client-2.6.5-2.el16.x86_64 and nut-2.6.5-2.el6.x86_64. With Fedora we were using nut-2.7.2-1.fc20.x86_64 and nut-client-2.7.2-1.fc20.x86_64.

What kernel versions?

We have had a number of recent reports of issues with USB 3.0 host controllers. While it seems like your UPS is getting picked up by the uhci_hcd driver, you might want to check if another USB port works better. Also, make sure you are using a decent-quality cable (no passive USB extenders, etc.).

I am also slightly suspicious of mtp-probe. We haven't done any testing with other programs trying to access the UPS at the same time, but there is some code in NUT to try and catch two NUT drivers from tripping over each other. But it only shows up in the Fedora output, and its messages seem closer to when the device is attached, rather than when it disconnects. I'm not sure if Fedora or CentOS have "server" builds, but I would recommend starting from the minimum software necessary and building up.

Charles Lepple
clepple at gmail

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