Re: [Lprof-users] usb device permissions

[Hal V. E. <hv...@as...>]

On Monday 22 June 2009 02:10:43 am Kai-Uwe Behrmann wrote:
> Hello,
>
> I'd liked to profile a monitor with LProf, but had less success.
> The attached error dialog poped up while accessing the measurement device.
> My difficulty was not so much that permissions are not perfect. I had
> rather spent a lot of time to find out, which file in the system I have to
> chmod to 0666.
> So frankly the location in the information window was useless to me:
> usb:/bus/0/dev - where is this in the system?
> After a while searching the archives and with the help of lsusb I found:
> /dev/bus/usb/002/009, umm.
>
> I know that the linux usb/permission system is a pure mess. E.g. many
> devices are mapped to some file but then this file is not communicated
> correctly. But with a little more verbose message in LProf, I would have
> been able to circumvent that quickly. Something like
> ... usb:/bus/0/dev (file:///dev/bus/usb/002/009) ...
>
>
> kind regards
> Kai-Uwe Behrmann

LProf uses the Argyll meter code.  Some of this message is directly from the 
Argyll meter support back end.  Specifically  "Configuring USB port 
'usb/bus0/deb )Xrite DTP94) to 1 failed with -1 (could not config 1: Die 
Operation ist nicht erlaubt)" is from Argyll and is all the information the 
LProf has other than what it was trying to do when this failed.  The rest of 
the message is an attempt to make it more meaningful.

The most likely cause is that you have not setup UDEV correctly for the Argyll 
meter code.  A simple chmod 666 of the device is likely not going to work.  
Another possible test is to try this as root to make sure that it is really a 
permission problem.  See the udev sections of this

 http://www.argyllcms.com/doc/Installing_Linux.html

web page.

A a side note the monitor calibration and profiling code is currently in a 
primitive state and is likely not going to work very well on anything other 
than a CRT.

Hal