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.

Update 2026-08-23: This happened again today. Below did not fix my problem; at brightness 1, things were washed out. Setting down to 0.5 helped me read, but wasn’t displaying as I am used to. Unplugging the display, power cycling, re-plugging it, then re-setting brightness to 1 seems to have fixed it. I checked a diff of xrandr --verbose before and after and saw no significant differences (just timestamps and the manually adjusted brightness value). Very strange.

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.

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