First install Android tools:
sudo apt-get install android-tools-adb
Open file (create it if necessary):
/home/[your-username]/.android /adb_usb.ini
and add next line in it:
0x2717
Open file:
/lib/udev/rules.d/69-libmtp.rules
and add next lines:
# Xiaomi Redmi Note 3 ATTR{idVendor}=="2717", ATTR{idProduct}=="ff68", SYMLINK+="libmtp-%k", MODE="660", GROUP="audio", ENV{ID_MTP_DEVICE}="1", ENV{ID_MEDIA_PLAYER}="1"
Restart services:
sudo service udev restart
Now you should be able to see your phone’s storage when you connect it to your computer over USB cable.