Switching display on or off has annoying delay

REPRODUCIBILITY (% or how often): 100*
BUILD ID = OS VERSION (Settings > About product): 4.2
HARDWARE (XA2, X10, X10 II, …): XA2, 10
UI LANGUAGE: Irrelevant
REGRESSION: (compared to previous public release: Yes, No, ?): No


Switching the display off or on has a delay of about half a second, but only if the display was previously in the other state for more than a few minutes. So say the display was on for 10 minutes and you switch it off (regardless of whether this is by hw-button or using the lock button from the menu), it does not immediately respond.

The same is true when turning the display on. If the display was only off for a short while this is quick, but when it’s been off for more than a few minutes it suddenly becomes slow.

The worst part is that during the delay the interface still responds to actions. So, locking the phone and putting it away might start a call, send a message, or do something else that you are not expecting.



  1. Switch on the display
  2. Keep it on for a few minutes
  3. Switch the display off


Toggling the display state should be instant - particularly switching it off


This may take a little while - causing unwanted UI interactions.


(Please ALWAYS attach relevant data such as logs, screenshots, etc…)


The same delay is, unfortunately, still there in 4.3

Unfortunately, this bug is still present in 4.4

I cannot reproduce this on my XA2.

I left the screen on for 15 Minutes, pressed the lock button and it locked immediatly (<1sec)

Either it is very device specific or something you have installed is causing this. Are you using any patches, or do you have something in mind that might be the cause?

It’s not patch-related. It happens to me on multiple devices, XA2 Plus and 10 II, the latter one without any kind of patches installed. I think it’s probably related to the whole proximity sensor toggling done by SFOS to avoid it hanging and causing issues.

BTW: Less than a second to lock is still slow, the screen should start dimming immediately, without delay.

How long is it taking for you?

Like I mentioned when opening the topic, it seems to be about half a second.

In that case it does not make a difference for me, if the screen was on for a longer time.
When I try hard I can click a button directly after pressing the switch.