Screen Brightness Issues [SOLVED] (sort of)

[buttmoist]

My keyboard brightness keys are not detected. I am using ACPI for all the power management, no xbacklight. Not that that mattered, because when I tried to set custom keybindings using xmodmap, they were completely ignored. Scankey doesn't detect my two screen brightness keys at all (it detects all other keys fine). My laptop only has a haswell era intel i3, so it is not an issue with a dedicated graphics card. I don't believe it to be a graphics issue at all since everything else works fine except for the brightness controls (I could be wrong since I have no idea where I'm at). I am using Xfce and Mate and neither detects my brightness keys. I can still set it via the command line using xbacklight, or the screen brightness panel item. But the keys themselves are non functional. This is not the first time I have run Gentoo, but it is the first time using it on this particular computer. Fedora never had an issue with the keys and even Arch worked flawlessly. I have enabled what I believe to be all the ACPI options in the kernel, all of Intel graphics options in the kernel (for my particular chip, which is an i915). I don't know what code output would help to solve this issue, all I know is that /sys/class/backlight has one intel_backlight option and nothing else. Modifying it did absolutely nothing.

This is becoming more and more frustrating, and I can find no information online regarding this issue. I have been researching this for over a month now and have gotten nowhere. Any help would be appreciated, thank you.

SOLVED: They way I solved this isn't particularly helpful to anyone else having this issue. I ended up swapping out my custom kernel for a genkernel. Today I tried to run on of my QEMU-KVM virtual machines but it wouldn't work because kvm wasn't enabled in the kernel. I cd into /usr/src/linux, run make menuconfig, and enable KVM. I save the config file, exit, and run make, make modules_install, make install, and grub-mkconfig -o /boot/grub/grub.cfg. I rebooted and everything worked. Screen brightness, virtual machines, you name it. I have no idea how or why it worked this time, but I plan to go through every, single option in the kernel and figure out a) what genkernel turned on or off, and b) try rebuilding the kernel so I don't have to have all of these extra modules that need loaded at boot. Thank you for everyone who tried to help and to those with a similar problem maybe try the genkernel, build the kernel manually (like in the steps I listed) and then work backwards building your custom kernel.

[_Nomad_]

Does running xev and pressing the keys in question yield any output?

oh, and what is the maker/model of the computer you're having issues with? Are the brightness keys integrated in the keyboard (i.e. function keys, Fx) or located seperatly?

[buttmoist]

[Hu]

If xev does not see the keys, then they are not generating X events and cannot be bound to a window manager (at least, not through a window manager's X key handling; some have alternate binding methods for other event types). Most likely, they generate some form of ACPI event, so you need to handle it by defining a handler for those ACPI events. What does acpid log when you press these keys?

[_Nomad_]

A quick google search found a page regarding that particular model at ArchWiki that suggest that the keys in question should output standard XF86MonBrightnessDown/XF86MonBrightnessUp. Are these the only nonfunctioning keys? Might there be a hardware issue?

[buttmoist]

I doubt it is a hardware issue since other distros have worked on it, and the live disks of other distros also worked. Even the live disk for Gentoo worked when I used it to install it originally. I just tried a genkernel kernel instead of my custom one but it doesn't seem to have helped.

[_Nomad_]

Then perhaps you need to enable a special hid-driver in the kernel. is CONFIG_HID_LENOVO set?