When Google announced Lollipop, the addition of native double tap to wake was a highlight for many people who have used devices with the feature. Subsequently, the Nexus 6 went through a will it, won’t it period when it came to supporting Double Tap to Wake. But now we know that the phone doesn’t, even though it once did, so developers have now set about enabling it on the handset and once you acquire one, you can too – if you’re willing to do a little work.
The little work includes unlocking your bootloader and rooting your phone, but from there it’s a trivial matter of just installing the APK of your choice to enable the feature. There’s two APKs available on XDA for free, with one available on Google Play for $1.14.
Both apps have been open sourced on Github, so if you’re interested in perusing the code which enables the workaround, you can.
There’s less and less reasons to root your phone, but with something as useful as double-tap-to-wake it’s certainly tempting to go down that path. Chainfire has of course done a fair amount of work on root for Lollipop, so it’s available. With new changes to Lollipop, once rooted, you’ll essentially have to go back to stock Android to get updates, but it could be worth it.