My home screen clock does not display the time correctly when in stand by. When I touch the screen to check the time it usually shows me what time it was when I last used the phone and it takes a few seconds until it updates to the correct time. It would not bother me so much but the problem is that I can not use the alarm function because it does not go off unless I touch the screen. Could you please shed some light on this? By the way, I own a Sony Xperia P.
The alarm should still go off - The display clock will not update whilst in sleep mode as there would be no point - so when you unlock your phone the screen display will refresh and correct the time from the internal time