Review Request 109792: Update 'dim display' algorithm.

[Sebastian Kügler]

> On March 31, 2013, 4:14 p.m., Àlex Fiestas wrote:
> > To be honest I don't like adding yet another configuration option by default, a configuration option that apparently is needed only in some systems.
> > 
> > There is no other alternative than this?
> 
> Danny Baumann wrote:
>     Well, I don't see any. I tried to approach this at the kernel level first, but the kernel people rejected the idea. But I don't see it as a big problem either: E.g. Windows (which isn't an example of overconfigurability) has a dimmed brightness setting as well. While it's required for my laptop, I think it can be useful for other people as well. When I hit the problem, at first I couldn't believe this isn't configurable either ;)
>     
>     BTW, one thing I'm not yet certain about is whether the option should be 'dim to' or 'dim by'. Currently it's the former, but the latter might it make more obvious that the value is relative to the non-dimmed brightness.
> 
> Sebastian Kügler wrote:
>     Just set the minimum brightness to 1 instead of 0. We're generally not adding config options for this kind of things.
> 
> Danny Baumann wrote:
>     That doesn't help though, as with intel-backlight 1 is still way too low to be visible. I think the value corresponding to acpi value 0 is about 5%. At this point, I think, I would alter the acpi behaviour again. Also, if the user had set the brightness to 0 before for some reason (e.g. because he's working in the evening), 'dim display' would suddenly make the display more bright.
>     In general, the problem is the different backlight interfaces just behave differently, which is why I think this problem can't be solved with a hardcoded value as long as it's not possible to detect the used sysfs file (which isn't the case as long as the used X driver provides a backlight interface via Xrandr).
>

The "dim can brighten up" is a different problem that needs a different solution, it's unrelated here.

I don't see how a config option solves this problem. Even with a config option, we still don't know what the default should be. Also, users are not going to look for such an option (which maybe says enough about the option itself). Users are going to hit the brightness slider when the brightness is too low, so 1 actually does make sense.


- Sebastian


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On March 31, 2013, 4:07 p.m., Danny Baumann wrote:
> 
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> http://git.reviewboard.kde.org/r/109792/
> -----------------------------------------------------------
> 
> (Updated March 31, 2013, 4:07 p.m.)
> 
> 
> Review request for kde-workspace and Solid.
> 
> 
> Description
> -------
> 
> This change does two things:
> - No longer dim display before the dim time set by the user elapses.
>   This fixes bug #304696
> - No longer assume that 0% display brightness produces a visible result.
>   This doesn't work with the intel-backlight backlight interface (as it
>   turns off the backlight at 0% brightness). According to the kernel
>   developers (see [1] and [2]), this isn't a safe assumption to make for
>   other backlight interfaces either. Instead of always dimming to 0%,
>   make the amount of dimming configurable.
> 
> [1]
> http://lists.freedesktop.org/archives/intel-gfx/2013-March/026152.html
> [2]
> http://lists.freedesktop.org/archives/intel-gfx/2013-March/026140.html
> 
> 
> This addresses bug 304696.
>     http://bugs.kde.org/show_bug.cgi?id=304696
> 
> 
> Diffs
> -----
> 
>   powerdevil/daemon/actions/bundled/dimdisplay.h 426640ca7a2a2d23044052710fdfb4b1f65617d1 
>   powerdevil/daemon/actions/bundled/dimdisplay.cpp 11554e3ba5d2f67d4d1de9d61c744c6c40a32d27 
>   powerdevil/daemon/actions/bundled/dimdisplayconfig.h 14b787937249a512cf958a31fd3bd71d6051540d 
>   powerdevil/daemon/actions/bundled/dimdisplayconfig.cpp bc116d6216c4624cbf14489d739d9d226fb70ff3 
> 
> Diff: http://git.reviewboard.kde.org/r/109792/diff/
> 
> 
> Testing
> -------
> 
> 
> Thanks,
> 
> Danny Baumann
> 
>

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