"You have a Logitech Mouse connected, and libusb was found at compile time, but it was not possible to access this mouse. This is probably caused by a permissions problem - you should consult the manual on how to fix this."

this is a very old problem.. there is already a bugreport but i didn't find any solution that would make it through a reboot...

there is this option to change the resolution since several years now and it never worked.. why is it still there at all?

I do not know why it is there, but this person also experienced a similar problem ( but with try to access any mouse data ). I believe Debian ( and therefore *buntu ) have a plugdev group that has the needed permissions, otherwise try here %7Bsolved-can-not- ... 728-2.html

Maybe try finding another utility that can do the job, and posting information about that to the bug may help provide information required to resolve it.

If you do a kdesudo systemsettings, then you can see the battery level, but still can't change the other things.

with sudo systemsettings i can change to 800 dpi ...
but it can't save it:

systemsettings(9039) LogitechMouse::save: Logitech mouse settings not saved - not implemented yet

That would be a bug report then for "Not implemented yet visible" functionality. If you find any other utilities which permit you to change the DPI, etc which are open source you may wish to add information about it to the bug report.

at this moment i use "lomoco" ... i wrote one line to "rc.local" (lomoco -8 ) to set the dpi to 800... it works.. but why is there a kde tool, if it can't do what it is supposed to do .. it is there since kde 3.0 or something.. it never did it's job

If lomoco also uses libusb to do its work, then it would likely be trivial to transplant the code into the logitechmouse section of the Mouse KControl Module.

yes, but you still need root privileges... therefore i used rc.local to automate it (unplugging and replugging the mouse would clear this setting - that's very annoying)

If distributions set the permissions of the device correctly ( with a usb or plugdev group with read/write access ) then as long as a user is a member of this group then it is not an issue.

I believe Debian based distributions already have the "plugdev" group, but users are not placed in it by default.