LG Nexus 4
Android 4.3 (USB DEBUGGING ACTIVE)
ADB 1.0.31 on Kubuntu 13
My /etc/udev/rules.d/51-android.rules is taken from here https://code.google.com/p/51-android/
Like i said everything i got with #adb devices command is:
List of devices attached
00b453e41****** offline
(i censored the id)
Any other info that could be userful?
Ok i solved by myself, it seems it was an issue of permissions. Just made my user:group owner of the /home/user/.android folder (and all files inside), the owner was root before and i think this was the problem. Now everything works.