display brightness & slider follows hw keys or mousing, but jumps about & brightness flickers at low end

Kevin, I can't reproduce this issue on an older dell latitude laptop. When pressing the brightness hardware keys (actually Fn + up/down arrow) the brightness slider moves accordingly, and then moving the slider correctly changes the brightness.

Note that I am running zesty with a locally fixed systemd package (see bug 1661568). I wonder if what you are seeing is a side-effect of the aforementioned systemd issue.

My proposal is to try again in a few days, when the fixed systemd package will have landed to zesty (hopefully). If the problem persists we can investigate further.

ok, this bug has evolved
to repro:
reveal the indicator panel for battery/brightness
either select drag element with mouse or choose up/down with hw brightness keys
the slider position will not respond precisely, jump about & at the extremes (max/min) settings there will be flicker between what seems to be 2 different settings

added a log per request look for "kg marker" i made sure to go to the minimum and keep pressing minimum and got the flicker.

The file also has all the other scenarios i saw earlier before the "kg marker"

And i also noticed that it's constantly spewing
handle_user_activity_changing_power_state
handle_user_activity_extending_power_state
back to back...like every second or so. definitely not optimal.

also, just noticed, if i rapidly hit hw key, i get the odd flicker between settings...if i go very slow, i don't get the flicker.

I can't see anything wrong happening with brightness on my laptop. Even playing real hard with the slider, the most I get is some lag and the slider catching up to my moves a second after I release the slider.

With buttons, everything is fine here.

I really don't see anything unity8 could be doing wrong.

I see some jitter when using the slider but it always corrects.
The hardware key shows no issue.
Samsung laptop, zesty