just disable the stamina mode and problem solved! the led notifications wont work properly if stamina mode is enabled... or even if u want to have led notifications in stamina mode..den u can download a third party app... 'illumination bar notification' from play store...it supports xperia sp... nd u can choose diffrnt colours for diffrnt notifications.. it even works in stamina mode without draining the battry... i too use my led notifications this way