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[Bug] Light sensor. [released]

asked 2014-10-15 23:33:24 +0300

niuran gravatar image

updated 2014-10-23 16:27:43 +0300

eric gravatar image

Sometimes,when i take out the phone of my pocket and the daylight is high, the screen appears with low luminosity, if i put the finger over the light sensor and retire it, the screen goes to maximun luminosity, that have to be from the beginning in order to be readable.

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The question has been closed for the following reason "released in a software update" by molan
close date 2016-10-13 17:33:03.594469

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I can confirm this behaviour, the brighter the environment is, the more often it happens. As niuran said, once you shortly cover the light sensor, it's working normal again until the next wake up in very bright environment. If this happens the sensor doesn't automatically correct, no matter how long you wait. The sensor area is clean at this moment.

Stefan P ( 2014-10-16 20:19:50 +0300 )edit

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answered 2014-10-16 13:08:09 +0300

spiiroin gravatar image

updated 2016-10-13 14:14:55 +0300

Sounds like the initial sensor reading is incorrect and does not get corrected until the sensor is disturbed - which would make this different problem from https://together.jolla.com/question/50935/screen-turns-on-sluggishly/

There has been internal reports of something similar, but so far I have not been able to reproduce it.

Just to be sure:

  • it does not happen every time?
  • when it happens it does not correct automatically (within a second or two)?
  • have you checked whether the sensor area is clean when it happens?

EDIT:

This was fixed in 2.0.0 (show up at changelog -> kernel-adaptation-sbj: [sbj] Fix saturated ALS lux reporting)

The als kernel driver retained previously reported value when it received fully saturated value (to switch to different measurement range). Which would be fine except that it was done for final range too -> When the device was taken from dark environment to bright sunlight, the reported light value easily remained at close to zero value.

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Try this to reproduce:

The screen display is set to its lowest brightness.

The phone is on a table, screen-side up, in landscape orientation with the light sensor in the upper left corner for left hand finger typing or the lower right for right hand finger typing. The test is done in a well-lit indoor environment. Run the native browser on the Jolla, and edit and post on Askbot's GUI.

Touch keys displaying near then far then near the light sensor.

The screen brightness changes depending where the hand is.

A way to address the issue might be to set brightness changes to be in accordance with the sensor's measurements averaged over a longer period, say four seconds (e.g. polling 2 or 4 measurements and taking the mean, minimum or maximum - whatever agrees best with relevant policy) to adjust brightness. Likewise, the brightness change might be made slower. At present the change is faster than my own eyes adjust to ambient light changes, or at least it seems that way.

rdmo ( 2015-01-08 14:03:32 +0300 )edit

@rdmo: The original issue is "initial brightness after turning display on is too dim" - /possibly/ caused by fully saturated sensor reading getting ignored when previous value was close to zero lux. What you're describing is most likely addressed here https://together.jolla.com/question/73121/brightness-changes-too-frequently-in-11127/

spiiroin ( 2015-01-08 15:24:24 +0300 )edit

Thanks for the tip.

rdmo ( 2015-01-08 15:36:56 +0300 )edit

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Asked: 2014-10-15 23:33:24 +0300

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Last updated: Oct 13 '16