[Nut-upsuser] mge-shut driver fails almost after every reboot

[Panagiotis Kritikakos]

Hello all,

OS name: FreeNAS 9.3
NUT version: 2.7.2
NUT installed method: Bundled with FreenNAS 9.3
Device: EATON 5SC 1000 
(http://powerquality.eaton.com/Products-services/Backup-Power-UPS/5SC.aspx?cx=5&wtredirect=www.eaton.com/5SC&GUID=B81251A4-F34E-4373-94B3-B4FB3D0CBCA8)

Problem description:

This was originally reported as bug to FreeNAS 
(https://bugs.freenas.org/issues/8049#change-41087) and was asked to 
post this upstream, so here it goes.

The issue with the driver has been seen in FreeNAS 9.3-STABLE. While the 
serial connection with the UPS (Eaton 5 5SC Serial with mge-shut driver) 
is working initially, almost after every reboot, the driver is failing 
with the message "UPS failed - Driver not connected". This was not the 
case with FreeNAS 9.2 and NUT 2.7.1.

Additional information:

~# /usr/local/libexec/nut/mge-shut -DD -a ups-filesrv01
Network UPS Tools - Generic HID driver 0.38 (2.7.2)
SHUT communication driver 0.84
Warning: This is an experimental driver.
Some features may not function correctly.

    0.000000     debug level is '2'
    0.000901     upsdrv_initups...
    0.000911     libshut_open: using port /dev/cuau0
    0.001034     entering shut_synchronise()
    0.037281     Communication with UPS established
    0.037289     entering shut_get_descriptor(n 01, 18)
    0.120208     shut_wait_ack(): ACK received
    0.371873     shut_wait_ack(): ACK received
    9.504230     shut_wait_ack(): Nothing received
    9.589858     shut_wait_ack(): ACK received
    9.742965     shut_wait_ack(): Nothing received
    9.867744     shut_wait_ack(): ACK received
    9.971912     - VendorID: 0463
    9.971919     - ProductID: ffff
    9.971923     - Manufacturer: Eaton
    9.971926     - Product: unknown
    9.971929     - Serial Number: unknown
    9.971932     - Bus: serial
    9.971935     Device matches
    9.971939     entering shut_get_descriptor(n 21, 9)
   13.027594     shut_wait_ack(): Nothing received
   16.028593     shut_wait_ack(): Nothing received
   16.055659     shut_wait_ack(): Nothing received
   16.055670     Max tries reached while waiting for ACK, still getting 
errors
   16.055674     entering shut_synchronise()
   16.197941     Unable to get HID descriptor ()
   16.197949     No matching HID UPS found

Thank you in advance!