How to connect Sony Xperia L with Ubuntu? How do I connect my Sony Xperia L in MTP mode with Ubuntu? If I connect in MTP mode, Ubuntu fails to read my files from internal storage.
What can I do?
That might depend on which Android version your device it running. Some devices additional support USB mass storage. Also: there are some packages you might install/update on your Ubuntu side, to support mtpfs (see e.g. answers here and here).

Alternatively, you might wish to go the "ADB way" (this is how I do it on my Ubuntu box). Here you would need a basic ADB installation (see: Is there a minimal installation of ADB?) and adbfs (see my answer here). In both cases, you can use graphical file managers as well as the command line to deal with your files.