Comment 190 for bug 1098216

(In reply to comment #59)
> It took me a while, but I just tested the patches on top on 3.8.2.

Thanks for testing.

> - brightness keys don't work in a tty or when no userspace daemon handles
> brightness
> - evtest /dev/input/event4 (Video Bus) sees KEY_BRIGHTNESS{UP,DOWN}
> - on Xfce with xfce4-power-manager default config
> - brightness is correctly changed when brightness keys are used,
> - 16 levels (with no smoothing) and OSD is behaving correctly

Sounds like it's working as expected.

> For comparison, on a 3.8.2 booted with acpi_osi="!Windows 2012" I get:
>
> - brightness keys work in a tty or when no userspace daemon is running (16
> levels, no smoothing)
> - evtest /dev/input/event4 (Video Bus) sees KEY_BRIGHTNESS{UP,DOWN}
> - on Xfce with xfce4-power-manager default config
> - brightness is correctly changed when brightness keys are used
> - I only get 9 levels, since brightness is changed both by the kernel and
> by
> xfpm
> - when disabling xfpm brightness keys handling I get 16 levels back (and I
> lose the OSD report)
>
> In my opinion the second behavior is better since that means brightness
> doesn't
> depend on userspace. And I wonder if KEY_BRIGHTNESS{UP,DOWN} should be sent
> at
> all, since job has already been done.

The upstream maintainers requested the first behavior and probably aren't going to take the patch to quirk these machines with ascpi_osi="!Windows 2012". However, nothing prevents you from continuing to boot with this option to get the second behavior.