I've been stuck with this issue for a long time. I have absolutely no way of controlling the screen brightness. I tried installing different software from AUR to no avail.
I'm trying to control the screen brightness using the F1 & F2 keys. I know it is done through i3 config but I don't think my distro has the necessary software/driver installed to control the screen brightness. I'm not 100% sure about it but that's what my assumption is.
The secondary issue is that, while on Chrome, F1 launches support.google.com, which would make decreasing screen brightness not possible while browsing the internet. I don't know if that's an i3 config file thing or a Chrome thing.