[Nut-upsuser] USB/UPS connectivity issue on Intel DP55KG Motherboard [DEBUG logs included upsd/upsmon/usbhid-ups]

Alan Stern stern at rowland.harvard.edu
Mon Oct 19 15:08:56 UTC 2009

On Sun, 18 Oct 2009, Justin Piszcz wrote:

> Thanks Alan,
> I have performed all of the steps you recommended, there is also a bug in
> the docs, the directory seems to be different, or at least if you have
> everything compiled into the kernel and not using modules.

> Start nut:
> # /etc/init.d/nut start
> Starting Network UPS Tools: upsdrvctl upsd upsmon.
> Within ~20-30 seconds it already broke:
> ============================================================================
> Broadcast Message from nut at p34.internal.lan
>          (somewhere) at 17:22 ...

Well, the usbmon trace shows that wherever the problem lies, it isn't 
in the kernel.  There were a few problems in the device itself -- it 
was queried for a report and did not provide any data.  The nut program 
should be smart enough to retry when this happens, but it didn't.

It did try to re-establish communcation with the device, but it appears
that nut got caught in a loop during this attempt.  During this loop
nut did nothing but transfer a bunch of string descriptors from the
device, over and over again at 2-second intervals.  The loop lasted for
almost a minute, until another device error occurred.  Then nut
recovered properly -- until a third error happened and nut got stuck in
its loop again.

Alan Stern

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