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

Shade Alabsa shade34321 at gmail.com
Wed Nov 19 02:45:54 UTC 2014

     We did notice that there were two categories. Is there a way if we
could determine if it is colliding?

We do have a USB analyzer so I'll see if that can be used to determine if
the UPS is disconnecting due to inactivity on the bus.


On Tue, Nov 18, 2014 at 8:40 PM, Charles Lepple <clepple at gmail.com> wrote:

> On Nov 18, 2014, at 6:28 PM, Shade Alabsa <shade34321 at gmail.com> wrote:
> > I then noticed that in ups.conf I did not set the pollinterval, we
> normally set it to 15, so I set it to test on a RHEL 6.6 machine which
> caused this issue to happen again. On our own custom system we took the
> poll interval out and prelim testing doesn't showing the repeated
> disconnects/reconnects. I started playing more with this pollinterval and
> noticed that up to 14, exclusive, it seems to be fine.
> pollinterval defaults to 2, so maybe the UPS is disconnecting due to
> inactivity on the bus? (It shouldn't, but it might be a workaround for
> other systems.)
> The usbhid-ups driver splits the polling into two categories: "quick
> updates", to catch OL/OB/LB transitions, and "full updates" to catch
> everything else. It is possible that the higher pollinterval values are
> colliding with the pollfreq interval of 30 seconds.
> The UPS is requesting that the OS (or in the case of Linux, a program like
> NUT which uses libusb) poll the interrupt endpoint at least every 40 ms,
> which is fairly often, and would cause higher CPU load. The defaults in NUT
> strike a compromise.
> Note that the man page for the MGE SHUT driver does recommend a higher
> value of pollinterval, but that is a special case (it is essentially USB
> over a serial cable, and the baud rate is not high enough for the defaults)
> and wouldn't apply to your UPS.
> --
> Charles Lepple
> clepple at gmail
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