Blank Screen when during a call
System Settings à
Cover the top Proximity sensor with thick paper
Click Als_ps Calibration
What is Proximity sensor :
The proximity sensor is common on most smart-phones, the ones that have a touchscreen. This is because the primary function of a proximity sensor is to disable accidental touch events. The most common scenario being- The ear coming in contact with the screen and generating touch events, while on a call.
To solve the issue, device manufacturers came up with the idea of a placing a proximity sensor close to the speaker, which will then detect any object in the vicinity of the speaker. If any object is present (ex. user’s ear), then the touch events can be assumed to be accidental & ignored.