powerdevil screen brightness linear vs nonlinear adjustment idea

[Sparr]

I have noticed that every laptop backlight brightness tool I have used,
including powerdevil and xbacklight and brightnessctl, increments and
decrements linearly through the available range of brightness values for
the backlight driver.

powerdevil attempts to split the range into 20 steps, so on my laptop with
a max_brightness of 120000 that is 6000 per step, and on my other laptop
with max_brightness of 7500 that is 375 per step. In both cases the
difference between steps 19 and 20 is almost indistinguishable, while step
1 is far above the minimum brightness and step 2 is very different from
step 1.

Manipulating the brightness manually on my two laptops, I can see that
there are many viable values below 5%, and I would happily give up some of
the less useful steps between 50% and 100% in exchange.

Assigning hotkeys to call brightnessctl directly I find that increasing by
25% and decreasing by 20% achieves a much more useful set of brightness
levels, approximately 100%, 80%, 64%, 51%, 41%, 33%, 26%, 21%, 17%, 13%,
11%, 9%, 7%, 5%, 4%, 3%, 2%, 1%.

I would like to ask, first, if users of other laptops see the same sort of
behavior, with 95% and 100% brightness being almost identical, while 5% is
far above the actual minimum brightness, and 5% to 10% is a significant
change.

If this situation is widespread, I might propose a change to the default
brightness control behavior. If it is not, I would ask for [sanction to
work on] configuration options that would allow users to change from linear
to nonlinear adjustment.

PS: I also think that the ideal number of steps is less than 20, possibly
closer to 10, and I wonder how much of that original choice of 20 might
have been influenced by the brightness of the lowest step (5% vs 10%). If
the lowest step can be closer to 1%, that decision might deserve a second
look.
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