I discovered this exact same issue, but with a slightly different environment. Perhaps it's not an Ubuntu bug but an issue with the kernel?
The brightness keys work in Windows. In linux, I can still adjust the brightness using the power manager slider despite the keyboard hotkeys not working. I am using the Lenovo Yoga C740, with my primary OS as Debian Buster. The brightness up and down keys (F11, F12) do not emit keycodes when pressed, even though holding down Fn and pressing F11 I am able to emit the function key behavior. These issues persist when using Ubuntu 20.04 through a live usb. I wrote a summary of my issues here: https://udia.ca/posts/2020/06/lenovo_c740/#hotkey-diagnosis -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1872311 Title: Brightness hotkeys not working on Lenovo S740 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1872311/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
