Samsung LCD + Display Rotate + Half screen black

Hello guys,

I’ve installed on a Raspberry Pi 3 the OSMC distro (2017-02) and I would like to put it in portrait mode.
On the /boot/config.txt file I’ve added display_rotate=1, which rotates the screen indeed, but I can only see half screen. I also tried lcd_rotate=2 etc, but did not work.
The other half is black and seems that the OS does not fit well.
This should run on a LCD Samsung.

Could you please let me know how can I fix this?
Thanks in advance.

Davide Ricardo