Huawei has cleverly implemented a feature called Face Tracking. In short, the phone will keep tracking your face to ensure the phone doesn’t turn off the screen or even dim it as long as you (or any other user) are looking at it. Basically, if it detects a face looking at the phone, the screen remains bright. So if you are reading something like an e-book or a lengthy article, the screen will be lit the whole time overriding the configured screen timeout. Pretty cool. But, it turns out that it might drain more juice than desired under certain conditions.
What’s the root cause?
I put my SIM card in the Honor View 10 yesterday and decided to give it a shot to see how it fares as a whole package from the perspective of the layman user and not a meticulous critique or a thorough analyst/developer. One thing that I noticed today was an erratically high battery drain rate while only using my phone in a typical light usage pattern. I was just typing on Slack and having a little chit-chat in the team’s slack workspace while listening to some music via my Bluetooth earphones, just as I normally do.
The phone lost about 14% or more battery in 1 hour. Not catastrophic, but not acceptable for a modern flagship Huawei device which is supposed to have one of the most efficient SoCs. Besides, the 3750mAh battery inside should not cause such a serious drain either. I tracked the CPU usage and found it to be very peculiar. The little cluster would keep resting on the intermediate 1018MHz as expected, but the big cluster would occasionally spike to near max frequencies and sometimes it even stays on a high frequency for like 5-7 seconds.
Then I noticed that nearly after 10 seconds of my last touch register (if I am not typing), this spike in the CPU frequencies occurs. I was baffled at first until I realized that I have set my screen timeout to 15 seconds. Once I changed it to 2 minutes, these spikes were nearly gone.
From this, we conclude that when the screen timeout is set to a lower duration, the Face Tracking will kick in more frequently, which is a feature that requires a lot of horsepower for a second or two and gets triggered before the timeout by 5 seconds.
More tests are needed
Now whether I actually saved battery by increasing the timeout to 2 minutes is yet to be confirmed with some stats. But for now, I can definitely notice the absence of these spikes. I’ll follow up this post if I can confirm that is the apparent reason behind the huge battery drain on my phone.
It would be great if I could disable this feature: it’s not like the Kirin 970 is very efficient to begin with.
Featured-Image: GSMArena
