# USBHID-UPS(8)

## NAME

usbhid-ups - Driver for USB/HID UPS equipment

## SYNOPSIS

usbhid-ups -h

usbhid-ups -a UPS_NAME [OPTIONS]

Note | This man page only documents the hardware-specific features of the usbhid-ups driver. For information about the core driver, see nutupsdrv(8).

## SUPPORTED HARDWARE

usbhid-ups brings USB/HID UPS monitoring to NUT on all platforms supporting USB through libusb. It should detect any UPS that uses the HID Power Device Class, but the amount of data will vary depending on the manufacturer and model.

At the present time, usbhid-ups supports:

- the newer Eaton USB models,

- all MGE USB models,

- all Dell USB models,

- all AMETEK Powervar UPM models,

- some APC models,

- some Belkin models,

- some Cyber Power Systems models,

- some Powercom models,

- some PowerWalker models,

- some TrippLite models.

For a more complete list, refer to the NUT hardware compatibility list, available in the NUT source distribution as `data/driver.list`, or on the NUT website.

You may use the `explore` driver option to gather information from HID UPSes which are not yet supported, to help add such support; see below for details.

This driver is known to work on:

- most Linux systems,

- FreeBSD (beta stage) and maybe other *BSD,

- Darwin / Mac OS X,

- Solaris 10 and illumos-based distributions.

## EXTRA ARGUMENTS

This driver also supports the following optional settings:

port = string

  Required option for all NUT drivers. Some value must be set, typically auto for drivers that handle USB connections.

  Note | This could be a device filesystem path like `/dev/usb/hiddev0` but current use of libusb API precludes knowing and matching by such identifiers. They may also be inherently unreliable (dependent on re-plugging and enumeration order). At this time the actual value is ignored, but syntactically some port configuration must still be there.

It is possible to control multiple UPS units simultaneously by running several instances of this driver, provided they can be uniquely distinguished by setting some combination of the vendor, product, vendorid, productid, serial, bus and/or device options detailed below. For devices or operating systems that do not provide sufficient information, the allow_duplicates option can be of use (limited and risky!)

vendorid = regex
productid = regex
vendor = regex
product = regex
serial = regex

  Select a specific UPS, in case there is more than one connected via USB. Each option specifies an extended regular expression (see regex(7) for more information on regular expressions), which must match the UPS’s entire respective `vendor`/`product`/`serial` string values (minus any surrounding whitespace), or the whole 4-digit hexadecimal code for `vendorid` and `productid`.

  Try lsusb(8) or running this NUT driver with `-DD` command-line argument for finding out the strings to match.

  Examples:

  - `-x vendor="Foo.Corporation.*"`

  - `-x vendorid="051d*"` (APC)

  - `-x product=".*(Smart|Back)-?UPS.*"`

bus = regex

  OPTIONAL, NOT RECOMMENDED.

  Select a UPS on a specific USB bus or group of buses. The argument is a regular expression that must match the bus name where the UPS is connected (e.g. `bus="002"` or `bus="00[2-3]"`) as seen on Linux in `/sys/bus/usb/devices` or lsusb(8); including leading zeroes.

  Note | Bus numbers are not guaranteed by the OS to be stable across re-boots, kernel driver reloads or device re-plugging (e.g. changing visible population of USB hubs).

device = regex

  OPTIONAL, NOT RECOMMENDED.

  Select a UPS on a specific USB device or group of devices. The argument is a regular expression that must match the device name where the UPS is connected (e.g. `device="001"` or `device="00[1-2]"`) as seen on Linux in `/sys/bus/usb/devices` or lsusb(8); including leading zeroes.

  Note | Device numbers are not guaranteed by the OS to be stable across re-boots or device re-plugging.

busport = regex

  OPTIONAL, NOT RECOMMENDED.

  If supported by the hardware, OS and libusb on the particular deployment, this option should allow to specify physical port numbers on an USB hub, rather than logical `device` enumeration values, and in turn — this should be less volatile across reboots or re-plugging. The value may be seen in the USB topology output of `lsusb -tv` on systems with that tool, for example.

  Note | This option is not practically supported by some NUT builds (it should be ignored with a warning then), and not by all systems that NUT can run on.

allow_duplicates

  OPTIONAL, NOT RECOMMENDED.

  If you have several UPS devices which may not be uniquely identified by the options above (e.g. only VID:PID can be discovered there), this flag allows each driver instance where it is set to take the first match if available, or proceed to try another.

  Normally the driver initialization would abort at this point claiming "Resource busy" or similar error, assuming that the otherwise properly matched device is unique — and some other process already handles it.

  Warning | This feature is inherently non-deterministic! The association of driver instance name to actual device may vary between runs! If you only care to know that at least one of your no-name UPSes is online, this option can help. If you must really know which one, it will not!

usb_set_altinterface = bAlternateSetting

  Force redundant call to `usb_set_altinterface()`, especially if needed for devices serving multiple USB roles where the UPS is not represented by the interface number `0` (default).

usb_config_index
usb_hid_rep_index
usb_hid_desc_index
usb_hid_ep_in
usb_hid_ep_out

  Force use of specific interface, endpoint, descriptor index etc. numbers, rather than defaulting to 0 (rarely other values in certain drivers for some devices known to use non-zero numbers). Specified as a hexadecimal number.

  As a rule of thumb for `usb_hid_desc_index` discovery, you can see larger `wDescriptorLength` values (roughly 600+ bytes) in reports of `lsusb` or similar tools.

LIBUSB_DEBUG = INTEGER

  Run-time troubleshooting of USB-capable NUT drivers can involve not only raising the common NUT debug verbosity (e.g. using the `DEBUG_MIN` setting in ups.conf(5) or protocol commands to change the `driver.debug` value), but may also benefit from LibUSB specific debugging.

  For the latter, you can set the `LIBUSB_DEBUG` driver option; alternatively you can classically export the environment variable `LIBUSB_DEBUG` before starting a NUT driver program (may be set and "exported" in driver init script or service method, perhaps via nut.conf(5)), to a numeric value such as `4` ("All messages are emitted").

  For more details, including the currently supported values for your version of the library, see e.g.:

  - https://libusb.sourceforge.io/api-1.0/

  - https://libusb.sourceforge.io/api-1.0/group__libusb__lib.html

subdriver=regex

  Select the USB HID subdriver for the device manually, where automatic match by device attributes alone does not suffice (e.g. new devices for which no `vendorid`/`productid` pair was built into any driver — but common USB HID support is anticipated, or for different-capability devices with same interface chips, notably "phoenixtec/liebert" and "mge").

  Run the driver program with the `--help` option to see the exact list of `subdriver` values it would currently recognize.

  Note | This option first checks for exact matches to subdriver identification strings, such as `"TrippLite HID 0.85"` (which are prone to bit-rot), and if there was no exact match — retries with a case-insensitive extended regular expression.

  Note | When using this option, it is mandatory to also specify the vendorid and productid matching parameters.

lowbatt=num

  Set the percentage at which the UPS will consider the battery charge as critically low, possibly resulting in a forced shutdown (FSD) situation.

  This value is typically dictated by the UPS device, although there is a fallback default value of 30 (in percent). Overriding this value can be helpful when the UPS sets this value to a lower percentage than intended.

offdelay=num

  Set the timer before the UPS is turned off after the kill power command is sent (via the -k switch).

  The default value is 20 (in seconds), or 60 for CPS devices. Usually this must be lower than ondelay, but the driver will not warn you upon startup if it isn’t.

  Note that many Cyber Power Systems (CPS) models tend to divide this delay by 60 and round down, so the minimum advisable value is 60 to avoid powering off immediately after NUT sends the shutdown command to the UPS. More details below.

ondelay=num

  Set the timer for the UPS to switch on in case the power returns after the kill power command had been sent, but before the actual switch off. This ensures the machines connected to the UPS are, in all cases, rebooted after a power failure.

  The default value is 30 (in seconds), or 120 for CPS devices. Usually this must be greater than offdelay, but the driver will not warn you upon startup if it isn’t. Some UPSes will restart no matter what, even if the power is (still) out at the moment this timer elapses. In that case, you could see whether setting `ondelay = -1` in ups.conf helps.

  Note that many CPS models tend to divide this delay by 60 and round down, so the minimum advisable value is 120 to allow a short delay between when the UPS shuts down, and when the power returns. According to support statement (for at least some CPS models), "our UPS systems are unable to set up power on delay".

pollfreq=num

  Set polling frequency for full updates, in seconds. Compared to the quick updates performed every "pollinterval" (the latter option is described in ups.conf(5)), the "pollfreq" interval is for polling the less-critical variables. The default value is 30 (in seconds), or 12 sec for CPS devices.

  Note | This setting is different from a `POLLFREQ` supported by upsmon(8) (for details see its upsmon.conf(5)).

pollonly

  If this flag is set, the driver will not use Interrupt In transfers during the shorter "pollinterval" cycles (not recommended, but needed if these reports are broken on your UPS).

interrupt_pipe_no_events_tolerance=num

  Set the tolerance for how many times in a row could we have "Got 0 HID objects" when using USB interrupt mode? This may normally be due to a device having nothing urgent to report, so the default value is `-1` and this situation is not handled in any way specially. However with some devices this was seen in conjunction with a frozen controller, where only a driver reconnection restored the data exchange (e.g. APC BXnnnnMI) — in such cases you may want to use a reasonable non-negative value here.

onlinedischarge_battery

  If this flag is set, the driver will treat `OL+DISCHRG` status as offline/on-battery.

  For most devices this combination means calibration or similar maintenance; however some UPS models (e.g. CyberPower UT series) emit `OL+DISCHRG` when wall power is lost — and need this option to handle shutdowns.

onlinedischarge

  DEPRECATED, old name for `onlinedischarge_battery` described above.

onlinedischarge_calibration

  If this flag is set, the driver will treat `OL+DISCHRG` status as calibration. Some UPS models (e.g. APC were seen to do so) report `OL+DISCHRG` when they are in calibration mode. This usually happens after a few seconds reporting an `OFF` state as well, while the hardware is switching to on-battery mode.

  Note | If it takes so long on your device that a shutdown gets issued, you may want to look at `upsmon` option `OFFDURATION` used to filter out temporary values of "administrative OFF" as not a loss of a feed for the powered load.

onlinedischarge_log_throttle_sec=num

  Set the minimum frequency (in seconds) at which warnings would be emitted for an otherwise not handled `OL+DISCHRG` device status combination. Negative values disable sequentially repeated messages (when this state appears and persists).

  If the device does not report `battery.charge`, the default value is 30 seconds (fairly frequent, in case the UPS-reported state combination does reflect a bad power condition and so the situation is urgent).

  If it does report `battery.charge`, by default the repeated notifications would only be logged if this charge is different from when the message was emitted previously (e.g. when the battery is really discharging).

  If both this option is set, and `battery.charge` is correctly reported, either of these rules allow the notification to be logged.

onlinedischarge_log_throttle_hovercharge=num

  See details in `onlinedischarge_log_throttle_sec` and `battery.charge` based log message throttling description above. This option adds a concept of UPS "hovering" a battery charge at some level deemed safe for its chemistry, and not forcing it to be fully charged all the time. As long as the current value of `battery.charge` remains at or above this threshold percentage (default 100), the `OL+DISCHRG` message logging is not triggered by variations of the charge.

lbrb_log_delay_sec=num

  Set to delay status-setting (and log messages) about device entering `LB` or `LB+RB` state.

  Some APC BXnnnnMI device models or firmware versions (reportedly 2023-2024), or APC BVKnnnnM2 device models, or APC BKnnnnM2-CH (a China-market-only model), frequently report "low battery", "replace battery", and "all ok" states changing rapidly within a couple of seconds, sometimes (but not always) preceded by `OL+DISCHRG` (presumably calibration).

  This setting lets the driver ignore short-lived states and only pay attention if they persist longer than this setting (and the device power state is `OL`).

lbrb_log_delay_without_calibrating

  Set to apply `lbrb_log_delay_sec` even if device is not calibrating.

disable_fix_report_desc

  Set to disable fix-ups for broken USB encoding, etc. which we apply by default on certain models (vendors/products) which were reported as not following the protocol strictly. This flag allows to disable the feature in particular device configurations.

  It is always possible that the vendors eventually release fixed firmware, or re-use identifiers by which we match suspected broken devices for unrelated products, so processing these fix-ups would be a waste of time there.

  It is also always possible that NUT fix-ups cause issues on some devices, whether due to NUT bugs or because the vendor protocol implementation is broken in more than one place.

powercom_sdcmd_byte_order_fallback

  Original `PowerCOM HID` subdriver code (until version 0.7) sent UPS `shutdown` and `stayoff` commands in a wrong byte order, than what is needed by actual devices seen in the field in 2024. The byte order is fixed to satisfy new devices by default since version 0.71. Just in case there are different firmwares out there with opposite behaviors, we provide this toggle to use old behavior in a particular deployment. Maybe it was just a bug and nobody needs this fall-back…

explore

  With this option, the driver will connect to any device, including ones that are not yet supported. This must always be combined with the "vendorid" option. In this mode, the driver will not do anything useful except for printing debugging information (typically used with -DD).

maxreport

  With this option, the driver activates a tweak to workaround buggy firmware returning invalid HID report length. Some APC Back-UPS units are known to have this bug.

interruptonly

  If this flag is set, the driver will not poll UPS. This also implies using of INPUT flagged objects. Some Powercom units need this option.

interruptsize=num

  Limit the number of bytes to read from interrupt pipe. For some Powercom units this option should be equal to 8.

waitbeforereconnect=num

  The driver automatically tries to reconnect to the UPS on unexpected error. This parameter (in seconds) allows it to wait before attempting the reconnection. The default value is 0.

  Note | for instance, it was found that Eaton MGE Ellipse Max 1500 FR UPS firmware stops responding every few hours, which causes usbhid-ups driver to detect an libusb insufficient memory error; in this case, when the usbhid-ups driver tries to reconnect too early, the activity sometimes led the UPS firmware to crash and turn off the load immediately! Setting this parameter to 30 seconds solved this problem (while 20 seconds were not enough).

## INSTALLATION

This driver may be not built by default. You can build it by installing prerequisites and using `configure --with-usb=yes`. Note that it will also install other USB drivers.

You also need to install manually the legacy hotplug files (`libhidups` and `libhid.usermap`, generally in `/etc/hotplug/usb/`), or the udev file (`nut-usbups.rules`, generally in `/etc/udev/rules.d/`) to address the permission settings problem. For more information, refer to the `scripts/hotplug/README.adoc` or `scripts/udev/README.adoc` files in NUT sources.

## IMPLEMENTATION

### Selecting a specific UPS

As mentioned above, the driver ignores the "port" value in ups.conf.

Unlike previous versions of this driver, it is now possible to control multiple UPS units simultaneously with instances of this driver running in parallel, provided they can be distinguished by setting some combination of the device-matching options.

For example:

    [mge]
            driver = usbhid-ups
            port = auto
            vendorid = 0463
    [tripplite]
            driver = usbhid-ups
            port = auto
            vendorid = 09ae

To monitor devices using the same vendor and product identification (e.g. two pieces of the same model), you would need to find a reliable unique matching criteria:

- The serial number is the best option, if populated.

- Link-level `bus`/`device`/`busport` may be unreliable (due to re-enumeration on a whim by the operating system).

- If nothing else helps, `allow_duplicates` may be an option in some cases.

### USB Polling and Interrupt Transfers

The usbhid-ups driver has two polling intervals. The "pollinterval" configuration option controls what can be considered the "inner loop", where the driver polls and waits briefly for "interrupt" reports. The "pollfreq" option is for less frequent updates of a larger set of values, and as such, we recommend setting that interval to several times the value of "pollinterval".

Many UPSes will respond to a USB Interrupt In transfer with HID reports corresponding to values which have changed. This saves the driver from having to poll each value individually with USB Control transfers. Since the `OB` and `LB` status flags are important for a clean shutdown, the driver also explicitly polls the HID paths corresponding to those status bits during the inner "pollinterval" time period. The "pollonly" option can be used to skip the Interrupt In transfers if they are known not to work.

## KNOWN ISSUES AND BUGS

### UPS reports 65535 sec (or 18:12:15) of battery.runtime capability

From a number of reports, it seems that some devices either can not report more than a 16-bit unsigned value in the standard field for remaining run time (vendor extended fields may exist but be unknown to the mapping tables in your current NUT driver build), or return `-1` for error and that gets treated as an unsigned 16-bit 65535 value.

According to some issue discussions, passing a battery test (calibration) can help the UPS re-estimate the time more correctly.

This problem may also be linked to a very lightly loaded large-capacity UPS. In some cases vendor documentation explicitly states that runtime calculation is not reliable with loads under e.g. 10%.

### Repetitive timeout and staleness

Some models tends to be unresponsive with the default polling frequency. The result is that your system log will have lots of messages like:

    usb 2-1: control timeout on ep0in
    usb 2-1: usbfs: USBDEVFS_CONTROL failed cmd usbhid-ups rqt 128 rq 6 len 256
    ret -110

In this case, simply modify the general parameter "pollinterval" to a higher value (such as 10 seconds). This should solve the issue.

Note that if you increase "pollinterval" beyond 10 or 15 seconds, you might also want to increase "pollfreq" by the same factor.

With certain devices and operating systems, notably MGE/Eaton USB Vendor ID (`0x0463`) on some versions of the Linux kernel, you might encounter poor interaction with the "USB HID quirk" mechanism, which precludes Linux from seeing the device as a `hid-generic` first, to hand it over to a NUT driver later. For more details, see the NUT FAQ document. This particular quirk can be tuned with a kernel boot parameter (via GRUB etc.):

    usbhid.quirks=0x0463:0xffff:0x08

Conversely, some hardware controllers may "fall asleep" when not contacted for too long; CPS devices are commonly associated with such behaviour. In this case, consider enabling `pollonly` flag and/or keeping `pollfreq` and/or `pollinterval` small.

### Got EPERM: Operation not permitted upon driver startup

You have forgotten to install the hotplug files, as explained in the INSTALLATION section above. Don’t forget to restart hotplug so that it applies these changes.

### Unattended shutdowns

The hardware which was used for development of this driver is almost certainly different from what you have, and not all manufacturers follow the USB HID Power Device Class specifications to the letter. You don’t want to find out that yours has issues here when a power failure hits your server room and you’re not around to manually restart your servers.

If you rely on the UPS to shutdown your systems in case of mains failure and to restart them when the power returns, you must test this. You can do so by running upsmon -c fsd. With the mains present, this should bring your systems down and then cycle the power to restart them again. If you do the same without mains present, it should do the same, but in this case, the outputs shall remain off until mains power is applied again.

### UPS cuts power too soon

Note that many Cyber Power Systems (CPS) models tend to divide `offdelay` by 60 and round down, so the minimum advisable value is 60 (seconds) to avoid powering off immediately after NUT sends the shutdown command to the UPS.

For many Cyberpower UPSs, `offdelay` must be set to `0` for normal behavior (the load is restored when AC power returns). Setting `offdelay` above `0` will restart the UPS load regardless of whether or not power has returned, and setting `offdelay` below `0` will disable the auto-power-on function of the UPS, keeping the load off even when power returns.

### UPS does not set battery.charge.low but says OK

Note that many Cyber Power Systems (CPS) models tend to allow only certain values for `battery.charge.low` and anything outside of the set of allowed values are rounded or ignored.

A shell loop like this can help you map out the allowed values:

    for i in `seq 90 -1 0`; do echo "set to $i"; \
        upsrw -s battery.charge.low=$i -u * -p * cps-big; \
        sleep 1; upsc cps-big battery.charge.low; echo ""; \
    done

For example, for CPS PR1000LCDRTXL2U model, the only allowed values are `[60,55,50,45,40,35,30,25,20]` and in some cases, your UPS may effectively not support a value of 10 for the `battery.charge.low` setting.

## HISTORY

This driver, formerly called newhidups, replaces the legacy hidups driver, which only supported Linux systems.

## AUTHORS

Originally sponsored by MGE UPS SYSTEMS.

Now sponsored by Eaton http://opensource.eaton.com

- Arnaud Quette

- Peter Selinger

- Arjen de Korte

## SEE ALSO

### The core driver

nutupsdrv(8)

### Internet resources

The NUT (Network UPS Tools) home page: https://www.networkupstools.org/historic/v2.8.4/