USBHID-UPS(8) 
=============

NAME
----

usbhid-ups - Driver for USB/HID UPS equipment

NOTE
----

This man page only documents the hardware-specific features of the
usbhid-ups driver.  For information about the core driver, see
linkman: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,
 - some APC models,
 - some Belkin models,
 - some Cyber Power Systems models,
 - some Powercom models,
 - some TrippLite models.

For a more complete list, refer to the NUT hardware compatibility list,
available in the source distribution as data/drivers.list, or on the
NUT website. You may use the "explore" driver option to gather
information from HID UPSes which are not yet supported; 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.

EXTRA ARGUMENTS
---------------

This driver also supports the following optional settings:

*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). 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.
 
*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). 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.

*pollfreq*='num'::
Set polling frequency for full updates, in seconds. Compared to the quick
updates performed every "pollinterval" (the latter option is described in
linkman:ups.conf[5]), the "pollfreq" interval is for polling the less-critical
variables.  The default value is 30 (in seconds).

*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).

*vendor*='regex'::
*product*='regex'::
*serial*='regex'::
*vendorid*='regex'::
*productid*='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)) that must match the UPS's entire vendor/product/serial
string (minus any surrounding whitespace), or the whole 4-digit
hexadecimal code for vendorid and productid. Try *-DD* for
finding out the strings to match.
+
Examples: 

 -  `-x vendor="Foo.Corporation.*"`
 -  `-x vendorid=051d*` (APC)
 -  `-x product=".*(Smart|Back)-?UPS.*"`

*bus*='regex'::

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", bus="00[2-3]"). 

*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.

INSTALLATION
------------

This driver is not built by default.  You can build it by 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 README
file in nut/scripts/hotplug or nut/scripts/udev.

IMPLEMENTATION
--------------

Selecting a specific UPS
~~~~~~~~~~~~~~~~~~~~~~~~

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 this driver, provided they can be distinguished
by setting some combination of the "vendor", "product", "serial",
"vendorid", and "productid" options. For instance:

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

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
---------------------

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.

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.

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
~~~~~~~~~~~~~~~~
linkman:nutupsdrv[8]

Internet resources
~~~~~~~~~~~~~~~~~~
The NUT (Network UPS Tools) home page: http://www.networkupstools.org/
