I've just updated my LG Optimus 4X HD from the latest stock ROM (4.1) to CM11 (Android 4.4). Access via ADB is only possible when either MTP or PTP are enabled; if I disable both, I only get:
$ adb devices List of devices attached ???????????? no permissions
I wouldn't really bother – but with PTP enabled, I always get a popup asking me to mount the "new device"; with MTP, additionally an error message for not being able to access the camera. This is pretty annoying: I never had it with this device before the upgrade, and I never experienced this with any other of my devices.
The "USB Connection" settings page only offers two checkboxes: MTP and PTP, the "Charge only" item is missing (and should obviously be reflected by unticking both MTP and PTP). Computer runs on Linux, in case it's relevant (and has no MTP software installed as I don't need it).
Is there any way to get rid of those annoying popups and still have ADB working? I'm fine with something to be executed via ADB, like
adb shell setprop <whatever> and, if proven stable, to integrate with