I’ve had this glitch twice now, where I wake up my external monitor and the screen is washed out with brightness. I can see enough to try to fix it, but it’s not the hardware brightness settings. The software brightness settings are out of wack.

I think both times I’ve ended up fixing this by rebooting, but I recently learned that I can use xrandr to control the software brightness like

xrandr --output DisplayPort-3 --brightness 1

You’ll have to adjust for your output device, of course. The brightness value appears to be a scale factor, so fractions dim the output and values greater than 1 lead to the wash out effect.

I’m not sure what toggled the xrandr setting, but at least next time I’ll have an idea of how to fix it.

Categories: Blog