Only the Xperia Tablet Z currently has a feature that enables you to wake the display with a double tap, however evidence points to Sony’s new flagship phone also having this function too. Sony Xperia Z, Xperia ZL and Xperia ZR owners may like to know that the latest AOKP custom ROM builds also enables this feature.
XDA member championswimmer used a kernel patch to enable Tap2Wake support. Apparently, the required drivers were already baked into the source code but were locked by Sony. Championswimmer managed to change a few lines in the source code to unlock Tap2Wake. This is a built-in function of the Synaptics ClearPad touch matrix, so battery drain shouldn’t be an issue either. For more information click on the AOKP links below.