Hi, I just experienced this issue the last few days. Started Thursday or Friday - sorted it out on Saturday after reading this, eventually getting the screen off(!) and then blowing into the proximity sensor. Downloaded SensorBox to test, and it seems to be working fine now, and works for calls as well. I’ve also enabled the ‘Power Button Ends Call’ option now in case it comes back, so at least I don’t need to remove the battery…
I’m wondering though - what else (if anything) is the proximity sensor really used for? It’s possibly used in apps of course, but I mean in Android OS. Looking at this problem from a different angle, couldn’t the phone turn the display back on either if the proximity sensor does not detect anything OR if the phone is held (relatively) flat based on the gyroscope? I don’t know about others, but I’m generally holding my phone reasonably vertically when calling, so I think this is a reasonable way to implement the functionality (and tbh until I experienced this issue, was how I assumed most smartphones worked!)
If people think this is a reasonable fix I’d be up for attempting to make a minor mod to the OS, behind some user activated option. (I don’t have experience modding Android, but I do work in software development).
Only relevant to geeks or Fairphone support folk:
A quick Google implies there’s actually two versions of FairphoneOS - ‘regular’ and OpenSource. Probably going well beyond the scope of the initial question here, but anyone know if the ‘regular’ and OpenSource versions are regularly (or ever) merged? Just wondering if I were to add a patch to the OpenSource version is there a chance it might be picked up in the ‘regular’ version eventually?