By default, when we plug the mini USB, it will transfer via MTP ( Connect as media device ).
Moreover, mounting the android phone using MTP mode decreases the size of the SD card to around 1 GB ( the real size is 16 GB ).
We have to change the mode of transfer to 'USB mass storage', and this is how to setup.
Settings > more
Wireless and networks > USB utilities
Click 'connect storage to PC', then connect the cable !
After connect the cable, my ubuntu sees two storages. First is the phone storage, another one is the SD card. cool!