I reflashed my PocketCHIP with 4.4 (primarily so that I could replace the screen sometime soon), and am struggling to understand how to set up brightness control.
I ran the setup script in Wanted: Noob guide to enabling PWM0 (or anything else) to enable pwm0, etc., but when I try to write values to the brightness thingamajig I get strange results.
Using the value in the post linked above yields an invalid argument error:
λ ~/ sudo sh -c 'echo 20 > /sys/class/backlight/backlight/brightness' sh: line 0: echo: write error: Invalid argument
Additionally, catting in 10 appears to turn the screen off, and any value between 1 and 9 turns it back on with a fixed (high) brightness level.
I’m kinda at a loss as to what’s going on here, so I thought I’d throw up a post here and see what sticks.
EDIT: Catting max_brightness returns 10, which makes sense given the information above, and catting type returns raw.