Brightness negative Fn key turns screen off halfway down range

Ask Fedora
1

Hi!

First time poster here. I’ve recently installed Fedora 35 on my Lenovo Ideapad Flex 5 14ARE05 (81X2).

Everything is working well bar some of the function keys. I was able to fix an issue with the Volume keys repeat pressing based on other forum entries, but I can’t find a solution (if it exists) for my brightness problem.

Essentially, if I’m at full brightness and I use the brightness negative function key, halfway down the range it switches the screen off. See pic attached below. At this point the next negative press will switch the screen off.
a20487c9f50437eed6601dc1ced6bd0733b0f920.png

Oddly if I press the postive brightness function key after it switches off, I can then hit the negative key twice before it switches off again. In this way I can actually get it to work it’s way down the range by pressing ±-±-±-… and so on until it reaches the bottom of the range. Then i can increase the brightness to halfway and reduce it all the way to zero again where it switches off at the correct point. It’s like it only has half the range on the negative presses before it invokes the turn off screen call.

Any thoughts on how I might fix this?

Would appreciate any help.

Thanks,

MD

2

Hi, usually if Fn keys not working properly, we could try with adding some kernel paramaters. Most of the time, for back light is by adding acpi_backlight=vendor.

If you’re using Fedora Workstation, you could add it with:

sudo grubby --args="acpi_backlight=vendor" --update-kernel=ALL

Then reboot your system to see the changes.

If above not work, you could remove it with:

sudo grubby --remove-args="acpi_backlight=vendor" --update-kernel=ALL

You could also try other parmeters from this page and find line with acpi_backlight=.

3

Hi Syaifur, thanks so much for getting back to me.

I tried the below but it just stopped the brightness control from working at all.

sudo grubby --args="acpi_backlight=vendor" --update-kernel=ALL

I will have a look at some of the other arguments in the link you shared and update if anything else works.

Appreciate the reply!