New Screen turns off when making or receiving a call

Jul 28, 2013
As above:
a call is made or received and the screen turns off, can not access any controls, such as speaker or keypad or mute.
When I press the home button the screen flashes, but cant press anything and then goes black again, power button does not work, back or settings button does not work, as in nothing happens.
When the power button is pressed or held down - nothing happens.
everything returns to normal after call ends (which has to be the other party hanging up!)
Samsung S2 GT I9100
Android vers 4.1.2 JZ054K
MIUI Vers MIUI-3.7.26
Baseband vers I9100XXLS9
Kernal vers 3.0.31-Siyah-S2-v6.0b4+