When should there be a screen brightness OSD?

[Thomas Pfeiffer]

On Saturday 18 January 2014 13:15:18 Martin Klapetek wrote:

> > > Truth is you don't need to know the /exact/ brightness or volume level
> > > in
> > > fullscreen video, you simply fiddle with it until it suits you. In this
> > > case it's maybe not as much about showing the exact percentage, but
> > > about
> > > providing visual feedback that you hit the correct keys and that they
> > > are
> > > working - I can imagine cases where users will press it couple times
> > > more
> > > to actually check if the brightness controls do work.
> > 
> > The main problem I used to have is when powerdevil changes the brightness,
> > especially when e.g. a TV is connected to the system. Kind of useless
> > then.
> 
> I thought about exactly this case. But if you disable the OSD in "passive"
> actions, you might also miss that the computer is about to power off your
> display (the brightness goes down every once in a while and when it's at 0,
> DPMS will kick soon...by default). So I guess you do want some kind of
> notification on external TV in case you left your power management enabled.

The moment I read screen brightness OSD, I thought "Ah yes, that annoying 
thing, now it's the time to discuss it!"

Honestly: Whenever I'm working on a laptop on battery, or - far worse still - 
on my WeTab with its super-aggressive screen powersaving, that screen 
brightness OSD annoys the crap out of me. Devices on battery tend to reduce 
brightness pretty quickly (and no matter how I fiddle with PowerDevil settings, 
that changes exactly nothing), so whenever I read some text, screen brightness 
is reduced a little every few seconds, each time showing that damn OSD on top 
of the text I'm reading. And of course whenever I move the mouse, the OSD 
shows again.

So let's have a close look at this. What information do I get from that OSD if 
it merely responds to automatic brightness reduction due to power management?
- That brightness is changed. Well, I can see that, right?
- To which level it is changed. Well, why would I care? Apart from the numbers 
being unreliable (on my laptop, 0% brightness is still bright enough to read 
when logically, it should be pitch black), the only thing I care about is 
whether it's still bright enough for me (in which case I do nothing) or too 
dark for what I'm doing right now (in which case I move the mouse).
- That my screen might be turned off soon. Well, as Martin G. pointed out: If 
the screen ever turns off while I'm watching a video, that sucks, and an OSD 
telling me that this is going to happen soon will not make the situation any 
less unpleasant

So, to be provocative: I would not only suppress the screen brightness OSD if 
there is a full-screen application running, but instead I would not ever show 
it when screen brightness is changed automatically. When it's changed 
manually, the OSD makes sense to give the user feedback on their action, but 
automatic screen brightness reduction is not something people need to be told 
about, since they see it.
Have you ever seen a mobile OS showing an OSD every time the brightness 
changes? I haven't, and since Plasma Active I know why: Because it would be 
annoying as hell.

Does anyone have an argument pro OSD on automatic brightness change which does 
not just reflect an underlying problem (such as the screen turning off while you 
watch a movie)?