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<p class="MsoNormal"><span style="mso-fareast-language:EN-US">This is exactly the sort of trouble I’ve been having.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Host machine is a physical, they’re in independent USB ports but appear to be different port on the same USB bus<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">udev helps identify them, why can't this be used in my case ?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"># ls -lrt /dev/ups-*<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">lrwxrwxrwx 1 root root 15 May 2 17:19 /dev/ups-1050g2 -> bus/usb/001/002<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">lrwxrwxrwx 1 root root 15 May 2 17:19 /dev/ups-850g2 -> bus/usb/001/003<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"># lsusb -d 051d:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Bus 001 Device 002: ID 051d:0002 American Power Conversion Uninterruptible Power Supply<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Bus 001 Device 003: ID 051d:0002 American Power Conversion Uninterruptible Power Supply<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">It appears to be periodically making a new device file - shortly after boot dmesg emits:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">[ 146.954100] usb 1-3: USB disconnect, device number 2<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">[ 148.045850] usb 1-3: new full-speed USB device number 4 using xhci_hcd<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">[ 148.191327] usb 1-3: New USB device found, idVendor=051d, idProduct=0002, bcdDevice= 1.06<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">[ 148.215953] usb 1-3: New USB device strings: Mfr=1, Product=2, SerialNumber=3<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">[ 148.237495] usb 1-3: Product: Back-UPS BE1050G2 FW:497200G -497300G<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">[ 148.256632] usb 1-3: Manufacturer: American Power Conversion<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">[ 148.273739] usb 1-3: SerialNumber: 9B2545A15277<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">[ 148.292906] hid-generic 0003:051D:0002.0003: hiddev96,hidraw0: USB HID v1.10 Device [American Power Conversion Back-UPS BE1050G2 FW:497200G -497300G ] on usb-0000:00:14.0-3/input0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">and the device files change to<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"># ls -lrt /dev/ups-*<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">lrwxrwxrwx 1 root root 15 May 2 17:19 /dev/ups-850g2 -> bus/usb/001/003<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">lrwxrwxrwx 1 root root 15 May 2 17:21 /dev/ups-1050g2 -> bus/usb/001/004<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"># lsusb -d 051d:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Bus 001 Device 003: ID 051d:0002 American Power Conversion Uninterruptible Power Supply<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Bus 001 Device 004: ID 051d:0002 American Power Conversion Uninterruptible Power Supply<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">and then 2 minutes later<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"># ls -lrt /dev/ups-*<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">lrwxrwxrwx 1 root root 15 May 2 17:19 /dev/ups-850g2 -> bus/usb/001/003<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">lrwxrwxrwx 1 root root 15 May 2 17:23 /dev/ups-1050g2 -> bus/usb/001/005<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"># lsusb -d 051d:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Bus 001 Device 003: ID 051d:0002 American Power Conversion Uninterruptible Power Supply<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Bus 001 Device 005: ID 051d:0002 American Power Conversion Uninterruptible Power Supply<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">I don't understand why udev is no help here. Is there any reference information i can look at to understand why (I can’t use udev rules to help) ?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm">
<p class="MsoNormal"><b><span lang="EN-US">From:</span></b><span lang="EN-US"> Charles Lepple <clepple@gmail.com>
<br>
<b>Sent:</b> 30 April 2026 12:25<br>
<b>To:</b> Gavin Davenport <gavdav@gavdav.net><br>
<b>Cc:</b> Nut-upsuser <nut-upsuser@alioth-lists.debian.net><br>
<b>Subject:</b> Re: [Nut-upsuser] Two APC UPS deivces, Fedora, slightly lost<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I haven't used NUT on Fedora, but your ups.conf seems to be on the right track (symlinks will not help for devices supported by usbhid-ups).<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">There are not many USB product IDs for APC UPSes, but do you get different IDs from "lsusb -d 051d:? Matching product IDs uses simpler logic than matching strings.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<div>
<p class="MsoNormal">A while back, we had issues with Linux guests not getting all of the USB information when on an ESXi hypervisor. That may not be the case if your host machine is physical, but there is still a possibility that the driver is having trouble
during the stage when it iterates through all of the USB devices to retrieve strings like serial numbers. Check the logs for any messages saying that the driver couldn't read the serial number - probably from something like "journalctl -t usbhid-ups". Specifics
of increasing the driver debug level may depend on your version of NUT (and whether/how the packager changed the systemd service definitions).<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<div>
<p class="MsoNormal">If that doesn't work, you can try plugging the UPSes into different USB ports (i.e. not into a hub) and using the "bus" parameter in ups.conf, which may need to be adjusted after a major kernel upgrade if the USB stack enumerates the buses
in a different order.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<div>
<p class="MsoNormal"><span style="color:black">-- <o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span style="color:black">Charles Lepple<br>
clepple@gmail<o:p></o:p></span></p>
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<p class="MsoNormal"><br>
<br>
<o:p></o:p></p>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<div>
<p class="MsoNormal">On Apr 29, 2026, at 6:55 PM, Gavin Davenport <<a href="mailto:gavdav@gavdav.net">gavdav@gavdav.net</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<div>
<p class="MsoNormal">I have 2 APC UpS devices – I have a group of 4 machines connected to various outputs on them and they are connected by USB to the same fedora host.<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">I’m having issues with nut reliabl discovering both devices<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<div>
<p class="MsoNormal">Here’s my ups.conf<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal"> [850g2]<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"> driver = usbhid-ups<o:p></o:p></p>
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<p class="MsoNormal"> port = auto<o:p></o:p></p>
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<p class="MsoNormal"> desc = "APC Back-UPS ES 850G2"<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"> serial = 5B1932T42066<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"> <o:p></o:p></p>
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<div>
<p class="MsoNormal"> [1050g2]<o:p></o:p></p>
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<div>
<p class="MsoNormal"> driver = usbhid-ups<o:p></o:p></p>
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<div>
<p class="MsoNormal"> port = auto<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"> desc = "APC Back-UPS BE1050G2"<o:p></o:p></p>
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<p class="MsoNormal"> serial = 9B2545A15277<o:p></o:p></p>
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<div>
<p class="MsoNormal"> <o:p></o:p></p>
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<div>
<p class="MsoNormal">I’m hoping nut will match on the serial number of the device.<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<div>
<p class="MsoNormal">I’ve been rather led astray by chatgpt making stuff up and then forgetting where it is – so I’m a bit confused about whether I try to have udev prepare the appropriate symlinks for nut<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">I’ve had this working (2 Ups devices being monitored, but all a bit hand-cranked). I can’t get it to survive a reboot.<br>
<br>
Are there any known issues with using 2 APC Ups devices which announce themselves very similarly ?<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Helvetica",sans-serif">_______________________________________________<br>
Nut-upsuser mailing list<br>
</span><a href="mailto:Nut-upsuser@alioth-lists.debian.net"><span style="font-size:10.5pt;font-family:"Helvetica",sans-serif">Nut-upsuser@alioth-lists.debian.net</span></a><span style="font-size:10.5pt;font-family:"Helvetica",sans-serif"><br>
</span><a href="https://alioth-lists.debian.net/cgi-bin/mailman/listinfo/nut-upsuser"><span style="font-size:10.5pt;font-family:"Helvetica",sans-serif">https://alioth-lists.debian.net/cgi-bin/mailman/listinfo/nut-upsuser</span></a><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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