SFPro2 Adaptative brightness stuck in "dim"

Discussion in 'Microsoft' started by javispedro, Jul 24, 2014.

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  1. javispedro

    javispedro Pen Pal - Newbie

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    Hello all,

    since yesterday I've found out that whenever I enable "adaptative brightness" in Charms->PC Settings->PC & devices->Power and sleep, brightness immediately gets set to the lowest level and gets stuck there even if I'm outside on a sunny day or even pointing a flashlight to the light sensor. Moving the brightness slider in the charms bar does absolutely nothing.

    This used to work before. It would brighten up or down according to sun level and use the brightness slider value as a "baseline".
    Unfortunately I am not sure when it broke. All I've installed for the latest 2 months are Windows and Office updates, according to the system log.

    At first I suspect a hardware failure but downloading the Sensors application from the Metro store shows that the ALS sensor correctly changes from ~10 lux (dark indoors) to ~15000 lux (pointing a phone flashlight to the sensor). So it does not seem a hardware problem unless these values are way off compared to other SFPro2s.

    So my question is: Does adaptative brightness work in SFPro2 with the recent updates? Does it still use whatever you set on the brightness slider as a baseline?

    (If I disable adaptative brightness the britghness slider does work, but I don't want to disable it!)

    EDIT: For some reason, I've found out that the default luminosity curve, SENSOR_PROPERTY_LIGHT_RESPONSE_CURVE, has been zeroed out on my system and is now "[0, 0], [0, 0], [0, 0], [0, 0]" :(

    If I add my own values to the ALRPoints key as hinted in http://superuser.com/questions/644538/customize-adaptative-brightness-in-windows-8 then it all works as it should, however, if I delete the ALRPoints key, instead of going back to Surface defaults it goes back to [0, 0].
     
    Last edited: Jul 24, 2014
  2. javispedro

    javispedro Pen Pal - Newbie

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    This problem eventually went away on its own. Weird, cause I even used system restore to try to fix it, to no avail.

    Another one of Windows mysteries...
     
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