Bug 313918

That is probably because your laptop is changing the screen hardware-wise :/ can you test with a newer kernel perhaps? does it help?

Also, can you try with a GNOME livecd using same kernel?

Thanks !

This reproduces in Kubuntu raring, which is a 3.8 kernel, so a newer kernel does not change it. Ubuntu 12.10 and 13.04 (Unity) both show a display brightness level OSD when I use the keyboard buttons. This is definitely an issue with KDE and the way it handles this for my specific hardware as another laptop I had worked without issue. How does KDE detect the screen brightness changes currently?

Can you execute:
kdebugdialog

Enable everything with "kded" or "powerdevil" on it

Then kill kded4 and execute it in a terminal so you can provide the output?

Created attachment 77787 [details]
kded4 debug output

I did as you instructed and while it was running changed the display brightness both to the max and to the min among other random changes. The X errors towards the end of the log occurred when the brightness popup showed itself for a second, but quickly vanished.

Oh... can you try by changing your plasma theme, or deactivating composite ?

What gpu driver are you using?

I did the previous test on a Kubuntu 13.04 live-cd. My laptop uses an intel gpu, but it also has an nvidia chip I can activate to see if it reproduces. The theme is the KDE default Oxygen and Air. The display pop-up used to work some time back, but I can't remember exactly when it stopped functioning.

As you pointed out this seems to be something related with X and drawing, let's see if we can figure it out.

Did you test disabling the composite?
Changing the widget style to Plastik or any other?

I tried all of what you suggested and no change. I have fired up xev to see if the key presses were getting handled by X and if X was registering them as the correct key, it is. I see X86BrightnessUp (or whatever the key is labeled and it matched what I saw on Ubuntu Unity where it does display the brightness bar correctly). I do not believe this is a bug with X, but more likely an interface changed and KDE wasn't updated to work with this change. I believe this as Ubuntu's Unity interface works perfectly and its using the same kernel and X as KDE.

If you could direct me at the code responsible for handling these hardware events, I would be willing to get my hands dirty trying to fix it.

you can start by kde-workspace/powerdevil/daemon/powerdevilcore.cpp look for "Increase Screen Brightness"

The technology that draws to the screen is completely different from Unity to KDE, though the underlying technologies are the same.

Try the following:
Desktop effects -> Advanced -> Qt Graphics system -> Native

Then either restart KDED or logout/login.

Due to a mishap with my laptop, I am unable to continue to debug this until, hopefully, I can get it fixed.

Git commit 245493d67eed84f56b62bceae56aa83c58891f64 by Dario Freddi.
Committed on 20/04/2013 at 20:12.
Pushed by dafre into branch 'master'.

Merge branch 'brightness-changed-signals'

Now brightness changes are always detected and streamed when hardware changes.
The cache itself is hardware based.
Related: bug 295982

M  +46   -10   powerdevil/daemon/backends/upower/powerdevilupowerbackend.cpp

http://commits.kde.org/kde-workspace/245493d67eed84f56b62bceae56aa83c58891f64

Does anyone know if this fix is in kde 4.11? I've tried kde 4.11 and 4.11.1 and see this issue. A clevo/system 76 laptop. Brightness keys change brightness but I get OSD, and KDE's battery applet does not reflect that brightness was changed (brightness progress bar still shows old brightness).

(In reply to comment #12)
> Does anyone know if this fix is in kde 4.11? I've tried kde 4.11 and 4.11.1
> and see this issue. A clevo/system 76 laptop. Brightness keys change
> brightness but I get OSD, and KDE's battery applet does not reflect that
> brightness was changed (brightness progress bar still shows old brightness).

In my case nothing have changed. I still get OSD in random situations.

Lenovo G780

this bug isn't fixed, same here on gentoo with 4.11.1 on lenovo x220 and x230

Reopening based on recent comments.

Same here.

I just commented to this bug: https://bugs.kde.org/show_bug.cgi?id=321310
...which seems to refer to the same problem.

TL;DR: KDE / xev do NOT notice Fn + BrightnessUp/Down key presses. There is no OSD / slider update. However, if I use the slider to change the brightness, everything works fine. Boot params: 'acpi_osi='

System: Lenovo T440p + Arch Linux. Current kernel: 3.12.8-1 mainline 64bit.

Regards

Hi all,
Fixed it for me on Lenovo T440p
https://bugs.kde.org/show_bug.cgi?id=323516#c24
Regards

Kernel parameters are just a workaround. This is still a KDE bug. On my T440s, xev DOES see XF86MonBrightnessUp and XF86MonBrightnessDown events and the brightness DOES change, but still, I get no OSD.

Have you tried going to configure global shortcuts and configure them with your laptop keys? 
(In reply to comment #18)
> Kernel parameters are just a workaround. This is still a KDE bug. On my
> T440s, xev DOES see XF86MonBrightnessUp and XF86MonBrightnessDown events and
> the brightness DOES change, but still, I get no OSD.

I have the default setting, which is indeed change brightness with XF86MonBrightness{Up,Down}. If I change it to something else, like Shift+F5, everything works, including OSD. If I leave it at Fn+F5 (XF86MonBrightnessDown), everything works, *except* OSD.

This bug is reported on libsolid which is the kdelibs4 version of the solid library.  It is now in maintenance mode.  If you think it should still be fixed in the KDE Frameworks 5 version of solid please move it to or report a bug on frameworks-solid or Powerdevil.

Hello! Sorry to be the bearer of bad news, but this project has been unmaintained for many years so I am closing this bug. Please try again with the latest version and submit a new bug to frameworks-solid if your issue persists. Thank you!