Hi everyone, since I haven’t experienced this issue yet there is a pattern to follow to replicate it?
What I mean is adaptive brightness turned off or on, specific app opened or in use, etc.
Or it’s something completely random that can’t be replicated?
For me its a few minutes sun irrespective of what I’m doing and I dont play games. And when it happens in sun, you will notice, because you will not see much.
Others notice during gaming, using duolingo app.
Adaptive brightness on or off doesnt matter.
It happens with Custom ROM so if software related than not OS related. I use FPOS.
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I don’t really understand the connection yet either. I got the FP4 last year in the summer. And before I installed Android 12, I never noticed this problem. Now I also notice it when I’m biking, when I check my messages or my route. Since I usually wear sunglasses, it’s even more noticeable than before when the display is at 100% brightness, but suddenly it’s hard to see anything. I did the same things with Android 11 and, as I said, I never noticed it.
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For me it mostly happens when I’m driving on a sunny day and running a navigation while charging the phone. It sometimes also happens without charging or with different apps, but not that often. So in my case it’s usually triggered by a combination of sunlight and heat.
Yes, it’s definitely a new issue which came with Android 12.
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Well, at first glance it would seem to be related to Fairphone’s version of Android12, but there are people using custom OSes (I remember mentions of Lineage and Calyx, there might be others, I’m too lazy to sift through those 167 posts).
So, it’s not Fairphone’s A12 version. But then again the problem seems to have appeared the exact same time Fairphone released their A12 upgrade. 
Could it be tied to the Android version (some A12 driver not playing nice with FP4’s hardware)?
Could everybody having this issue and using a custom ROM please state which Android version they run?
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I’m using Lineage OS with Android 13 and I also have this effect.
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Custom ROMs usually use Fairphone’s proprietary blobs, so this bug can very easily be contained in them.
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Sure. But then again people with custom ROMs having had Android 12 before Fairphone released its own Android 12 didn’t state any similar problems (AFAIK).
Did those ROMs get updated with Fairphone’s buggy drivers? (genuine question)
I don’t know how Android manages its drivers, but I would assume (maybe wrongly) that Fairphone’s OS is pretty much vanilla Android, using manufacturer-supplied drivers. They don’t seem to have the infrastructure to make their own.
So, where/when/how was the problem introduced?
I have this issue and I am running CalyxOS 4.9.4 (Android 13).
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The same form and conditions apply to me.
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Same problem here, since the Android 12 update. Sometimes I notice it happens inside my house, but most of the time outside.
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That really seems to be the main problem. If it is in other versions of the operating system, I can’t explain it any other way. If these drivers are used in other ROMs, this is indeed the only logical connection. This would also be comparable to the Bluetooth audio bug, which also exists in other ROMs.
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for me it is happening inside the house as well. I guess there is a certain bias in recognizing when it happens as inside you might not even notice it - opposite to outside and even more in direct sunlight. so I doubt that heating up or the sensing of very bright surroundings is the trigger for the issue.
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Thanks everyone.
Today I have been able to reproduce the issue.
Outside with direct sunlight, after some minutes, the brightness decreased at almost no readable level.
Tried inside with a direct light source on the sensor to check if it’s some bug with the light sensor, bit didn’t happen.
It seems like an overheating protection that as some point it’s triggered, but not sure.
Tomorrow I will try to make a logcat with adb shell and my laptop while outside with direct sunlight.
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I have the exact same issue! I that it was something I only had. It happens the same to me, after a while it randomly dims and I can’t get it back to the maximum brightness.
That doesn’t necessarily mean anything, because unless you have some WWII anti-aircraft searchlights, the sun is quite a lot brighter… 
You should try to isolate the factors, i.e. try direct sunlight in a cold environment, normal (sunny, hot) sunshine conditions but not at full brightness (a sliver of neutral filter on brightness sensor), strong lamp and phone getting hotter (for instance charging), and so on…
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Now I’m on eBay, trying to find a WWII anti-aircraft searchlights. 
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The anti-aircraft searchlight was hard to get.
But I have done some logcat while the brightness dimmed, with direct sunlight and while charging.
Brightness level set to 100% without the auto adjust.
It’s not easy because there are a lot of messages and errors/warning.
The only useful to me are these:
06-08 16:44:55.574 1736 2088 V DisplayPowerController[0]: Brightness [0.05] reason changing to: 'manual [ dim ]', previous reason: 'manual'.
At some point it becomes [ dim ], probably it means dimmed.
06-08 16:44:55.581 1736 2496 E DisplayDeviceConfig: requesting nits when no mapping exists.
06-08 16:44:55.582 1736 2496 E DisplayDeviceConfig: requesting nits when no mapping exists.
Probably a missing configuration for the nits mapping of the display.
06-08 16:46:37.468 988 1139 I android.hardware.thermal@2.0-service.qti: uevent triggered for sensor: quiet-therm-usr
Then some thermal sensor trigger an event.
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Thanks a lot for the investigation. I copied it to the beta gitlab.
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simply unbelievable. I find it really fascinating when you know a system so well, when you can search for mistakes at this level. That simply has to be praised.
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