[Nut-upsuser] newhidups, udev, usb, and frustration

Peter Selinger selinger at mathstat.dal.ca
Sun Sep 17 02:14:05 UTC 2006


Hi Denis,

the /dev/hiddevX devices are used by kernel drivers and are mostly
useful for things like mice and keyboards; libusb (and therefore
newhidups) does not use them. As you have already found out, it only
looks at /proc/bus/usb/XXX/YYY.

There are two separate issues. One is, can you get the driver to work
running as root? I.e., run upsdrvctl and upsd with "-u root". If this
works, then the second issue is permissions. (If it doesn't, try the
latest nut version from SVN; newhidups is being actively developed,
and 2.0.3 is a relatively old version).

The mechanism for automatically setting permissions of the
/proc/bus/usb/XXX/YYY devices is "hotplugging"; see scripts/hotplug or
scripts/hotplug-ng in the nut distribution. I have used this under
Fedora Core 4, and it seems to work reasonably well. 

-- Peter

Denis Hainsworth wrote:
> 
> Hello,
> I hope someone can help me.  I'm trying to get this all working without
> some stupid hack.  So far no dice.  Not sure if there is a new feature
> in CVS or something that might help. I'd appreciate any suggestions.
> 
> Got a belkin F6C550-AVR.
> redhat FC3ish system
> libusb-0.1.8-3
> nut-2.0.3-0.fc4.2
> udev-039-10.FC3.8
> 
> Now first off while udev is nifty, but the whole usb udev subsystems
> were driving me crazy.  add to that the fact that aparently my version
> of libusb doesnt pay attention  to udev devices as well as the fact that
> for a while I had fc4 udev which installed fine on my system but
> apparently is broken in some way since I couldn't get any rules to
> apply.  backrevving to fc3 udev and i am in a good place. if i plug the
> ups in i see it show up, udev follows my rules and updates the group and
> permissions for both /dev/hiddevX and /dev/usbdevX devices.  I can also
> make udev create a symlink to usbdev if I wanted to.  here's the part
> that has been driving me crazy.  it seems like newhidups uses perhaps
> some library calls from libusb to discover usb devices??  it appears
> that it will only pay attention to /proc/bus/usb/XXX/YYY devices.  since
> udev(or at least my version of it) doesnt do anything with these devices
> I can use udev rules to fix the persmissions and newhidups will only
> work if I run it as root.  there are several things that could fix my
> situation and i was hoping someone would know if any exist.
> 
> o can you tell nut through a conf file to run as root? i believe the
> package i am using from fc4 uses user "nut".  I'd like to stick with the
> package I have then run my own version.  this is the worst way to make
> this work but it will work.
> 
> o is there a version of libusb and/or nut that would let me specifiy a
> /dev device for newhidusb to look at instead of scanning what seems to
> be /proc/bus/usb/XXX ?  i cant tell udev to create a symlink and so I
> dont need newhidusb to scan for devices but nothing I seem to do appears
> to make it look at /dev/hiddev0 etc.   this is my preferred way to make
> this work since i will be using standard udev configs and simply
> pointing nut at the devices i create.  all very straight forward.
> 
> Like I said at the beginning I have a somewhat monsterous distro that I
> upgrade as I need things.  for example I only got udev working so I
> could use nut.  udev seems to be completly functional now and now I
> discover newhidups doesn't even seem to use its devices.
> 
> hopefully i am missing something simple, but i have combed the web for
> several days and experiemented for hours without being able to get it
> working how I would like.  so I hope someone can help.
> 
> thanks
> -denis
> 
> 
> 
> -- 
> ____________________________________________________________
> Denis Alan Hainsworth     | http://www.cs.brandeis.edu/~denis/  
> denis at alumni.brandeis.edu | "Life is just one big sad christmas."
> 
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