I upgraded the server using Tripp Lite to CentOS-8, and found that the newer kernel-4.18 tries a power cycle with standard conforming hubs automatically. This excerpt from dmesg shows the kernel power cycling the USB port:
[1362889.686300] usb 2-1.3-port4: disabled by hub (EMI?), re-enabling...
[1362889.686538] usb 2-1.3.4: USB disconnect, device number 21
[1362890.647976] usb 2-1.3-port4: Cannot enable. Maybe the USB cable is bad?
[1362891.487961] usb 2-1.3-port4: Cannot enable. Maybe the USB cable is bad?
[1362891.488185] usb 2-1.3-port4: attempt power cycle
[1362892.507703] usb 2-1.3.4: new low-speed USB device number 24 using ehci-pci
[1362892.556075] usb 2-1.3.4: New USB device found, idVendor=09ae, idProduct=3016, bcdDevice= 0.02
[1362892.556079] usb 2-1.3.4: New USB device strings: Mfr=3, Product=1, SerialNumber=5
[1362892.556082] usb 2-1.3.4: Product: TRIPP LITE UPS
[1362892.556084] usb 2-1.3.4: Manufacturer: Tripp Lite
So, while the Tripp Lite USB controller is still braindead, you may no longer need this package. For those on older kernels, or to find out what kind of hub to buy to make your Tripp Lite work properly, read on.
As part of upgrading my home data center, I bought a new UPS unit with longer runtime and AVR. The good news is that the new Tripp Lite SMART1500LCDT has a 50 minute runtime at 18% load (versus 35 minutes with my old APC 1500). It also has robust AVR (Active Voltage Regulation) that is confirmed to compensate for switchover to generator power.
The bad news is that they totally screwed up the USB port needed for the server to monitor the UPS. It locks up every few days, and even resetting the hub controller does not reset it - it ignores the reset and address assignment requests from the hub, i.e. it does not implement the mandatory reset feature of the USB 2.0 standard. Reviews indicate that even their proprietary Windows software is stymied by this defect, but Windows users accept it as par for the course, naturally.
We can reset the USB port on the UPS by cycling power for the port
on a USB compliant hub. Nut can detect the port failure, and run a script, but
the script (naturally) runs as the nut user, and doesn't have privilege
to reset USB ports. Instead, we append to /var/log/ups.log,
and use incron to run the upsreset script as root.
Add root to /etc/incron.allow. It is not a good idea to allow arbitrary
users access to incron until the package fixes some security problems.
Although a self-powered hub is not required to implement per port power switching, the hub MUST support the Powered-off state for all ports. Additionally, the hub MUST implement the PortPwrCtrlMask (all bits set to 1B) even though the hub has no power switches that can be controlled by the USB System Software.
While most USB microcontrollers used in hubs properly implement one or both of these options (controlled by configuration pins), unfortunately, it seems that nearly all actual USB hubs in a box on the market ignore this mandatory feature, and just hardwire Vcc on all ports to 5V. I am using a Linksys USB2HUB4, other working hubs are listed below.
Copyright (C) 2016 Stuart D. Gathman
Author: Stuart Gathman
Control USB power on a port by port basis on USB hubs with port power switching.
Originally created NIIBE Yutaka and published to Github by Joel Dare on January 31st, 2013.
This only works on USB hubs that have the hardware necessary to allow software controlled power switching. Most hubs DO NOT include the hardware.
You can control the power on a port using the following command.
sudo hub-ctrl -h 3 -P 1 -p 0
That says to control hub 3 (-h 3) port 1 (-P 1) and to turn the power off (-p 0). You can also use ”-p 1” to turn the power back on.
You can also specify the USB device based on the BUS and DEV numbers. Use the following command the list the currently connected devices. It's useful to run this with the device disconnected and then again with the device connected so that you can tell which device is the one you are trying to target (the Targus in my case).
lsusb
Now that we know the BUS and DEV numbers, we can control the power using those numbers as well. Here's the command for that.
sudo hub-ctrl -b 001 -d 005 -P1 -p 0
This time we are controlling the device on BUS 001 (-b 001) device 005 (-d 005) port 1 (-P 1) and turning the power off (-p 0).
The following is a list of Hubs that are known to have the hardware necessary to allow power switching.
- D-Link-DUB-H7-High-Speed-7-Port (Tested with old Silver versions (A3, A4 & A5). Also tested with newer Black version C1).
- Elecom: U2H-G4S
- Sanwa Supply: USB-HUB14GPH
- Targus, Inc.: PAUH212
- Hawking Technology: UH214
- B&B Electronics: UHR204
- Belkin: F5U701
- Linksys: USB2HUB4
Copyright (C) 2006 Free Software Initiative of Japan
Author: NIIBE Yutaka
This file can be distributed under the terms and conditions of the GNU General Public License version 2 (or later).