[Nut-upsdev] Work around for power recycling after shutdown.return - TSSHARA UPS - nutdrv_qx driver - megatec protocol

Daniele Pezzini hyouko at gmail.com
Wed Feb 28 04:41:03 UTC 2018

2018-02-27 14:51 GMT+01:00 Jairo Rotava <jairo.rotava at gmail.com>:
> Hi,
> I had an issue where after returning the power from a shutdown.return the
> ups would do another shutdown.return during the boot, and kept this forever.
> After some investigation I found the problem is a bug on the ups - TSSHARA
> model, driver nutdrv_qx: every time I shutdown with return, and reconnect
> the usb after the power is back it would start another shudown.return cycle.
> When I used my rapsberry pi on it they would cycle forever.

Jairo, what's the exact model of the UPS?
Version of NUT/nutdrv_qx?

Is the monitoring system (the one running nutdrv_qx) turned off by the
shutdown process?
Does this odd behaviour happen even if the 'stayoff' flag is used?

> I tested the shutdown.return using the upscmd and I didn't see this
> behavior, so I finally find out that is I sent a dummy command to the USP
> after the shutdown.return it would not show the problem. My guess is that
> the UPS firmware keeps the last command on memory and when the USB is
> reconnected it runs it.

When you experience this problem, does the UPS completely turn off
itself before restarting?

> I changed the nutdrv-qx driver (megatec protocol) and added a dummy info
> read after the shutdown command and the system is working fine. But I don't
> think this is the best way to fix this patch. What should be the best
> solution for this?

If possible, having TS Shara fix their firmware, if it's really broken.

> I end up using the original nutrv_qx file and modified the shutdown script
> to something like this
> /lib/nut/nutdrv_qx -a tsshara -k; /lib/nut/nutdrv_qx -a tsshara
> The last call is just to send some different cmds to the UPS so is does not
> recycle in the middle of the boot.
> I would like to know how can I contribute to get solve this issue with the
> tsshara ups.
> Regards
> Jairo
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