Brightness changing

Zneex wrote:

have a macbook pro 13 2014. Everything works fine on mac os mojave. When updating to mac os Catalina, changing the brightness of the screen does not work. The buttons themselves work, that is, you can see the brightness change icon on the screen, but the brightness does not change. I have been using brightness slider for a long time. Deciding to upgrade to mac os big sur, I was faced with the fact that when you click on the buttons, nothing happens at all, even the brightness change icon is not shown. And also when you exit sleep mode, the macbook itself works, but the screen does not. What can be in?

https://discussions.apple.com/content/attachment/acbb0b53-4a2a-4879-8f51-7f59ad96dfbe

Try resetting the SMC How to reset the SMC of your Mac - Apple Support

if no resolve—

Try resetting NVRAM/PRAM Reset NVRAM or PRAM on your Mac - Apple Support

(get at least two-three rounds of the chimes when holding the NRAM Reset)