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Set backlight brightness on HDMI 5" 800x480 Display Backpack
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Set backlight brightness on HDMI 5" 800x480 Display Backpack

by marsroverdriver on Sun Feb 17, 2019 6:43 pm

I'm making an alarm clock using the HDMI 5" 800x480 Display Backpack - With Resistive Touchscreen (product ID 2260). It's great, but it's awfully bright in the middle of the night. Can I adjust the backlight brightness from Linux? (I'm driving it with a Raspberry Pi 0.)

When xbacklight had no effect, I tried setting the gamma -- but neither xgamma nor xrandr's gamma-setting functionality had any effect, either. (I am running an X server, not going direct to the framebuffer, in case you're wondering. :-) The /sys/class/backlight/ directory appears to be empty, which is probably not a good sign. :-/

How should I do this?

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Re: Set backlight brightness on HDMI 5" 800x480 Display Back

by adafruit_support_carter on Tue Feb 19, 2019 2:10 pm

For HDMI, you can not do this unfortunately.
https://learn.adafruit.com/adafruit-5-8 ... /faq#faq-6

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Re: Set backlight brightness on HDMI 5" 800x480 Display Back

by marsroverdriver on Wed Feb 20, 2019 1:12 am

Argh. :-( Well, thanks -- is there info about how to do it on the hardware?

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Re: Set backlight brightness on HDMI 5" 800x480 Display Back

by adafruit_support_carter on Wed Feb 20, 2019 2:32 pm


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Please be positive and constructive with your questions and comments.