Bug 308757

Created attachment 74830 [details]
kded4 log

I'm having the very same problem on my Toshiba Qosmio X300. I can still adjust backlight through "/sys/class/backlight/acpi_video0", so I'm quite sure it's a KDE problem. I remember the backlight adjustment working perfectly in 4.9.0.
I have an nVidia 9800M card with 310.14 proprietary drivers.

Additional (and confusing) info: brightness keys started working again. There was no upgrade between.

I am having the same problem, I am using the following:

Fedora Linux
kernel    : 3.6.6-1.fc17.x86_64
nvidiabl : 0.80
KDE       : 4.9.2

I can control it using the interface file "/sys/class/backlight/nvidia_backlight/brightness" with the "echo" command, previous to 4.9.2 version of KDE, I had a problem with the kernel's module pata_acpi and I could not start up the system for about 2 weeks, just recently I was able to start it again, everything works but KDE's hotkeys for monitor brightness.

can you try with other kernel

for me with kernel 3.4 that work and stoped to work with 3.6

i have a toshiba z830

There were changes in nvidia driver 304.60 that broke brightness control on laptops:
"Added support for the "Backlight" RandR output property for configuring the brightness of some notebook internal panels."

Discussions of the problem:
http://phoronix.com/forums/showthread.php?74441-NVIDIA-310-14-OpenGL-4-3-Threaded-Optimizations/page7 (top post on page 7)
https://bbs.archlinux.org/viewtopic.php?id=151119
http://www.nvnews.net/vbulletin/showthread.php?p=2579087

The bug was fixed in 304.64:
"Fixed a regression in backlight control functionality on some notebook configurations."
- so brightness control via ACPI (/sys/class/backlight/...) works now, but KDE plasma (?) applet and hotkeys don't work.

So it's reasonable to say the problem lies in KDE/nvidia interaction and not in the kernel.

I don't know where to look from here, but I hope this helps.

Um, yeah, forgot to mention: we have KDE 4.9.3 in archlinux already, and the problem persists.
Just in case.

Don't work fn + up/down keys

It's work:
echo 0-7 > /sys/class/backlight/acpi_video0/brightness

Kernel: 3.6.6
Archlinux
Nvidia: 304.64

does this happen without a suspend 2 ram?

i got this problem only after a suspend 2 ram

(In reply to comment #9)
> does this happen without a suspend 2 ram?
> 
> i got this problem only after a suspend 2 ram

Yes, always, after reboot too.

My notebook samsung R730. In Gnome all works, for example.

 Screen:
The fn keys that control the brightness work as long as the laptop does not get suspended. If the laptop is suspended then upon resuming the fn keys no longer work. The fix is as follows:
add

acpi_backlight=vendor

to /etc/default/grub under GRUB_CMDLINE_LINUX_DEFAULT, then run update-grub. After rebooting, this will remove the acpi_video0 from /sys/class/backlight/ leaving you just with intel_backlight and toshiba. Upon resuming with these settings the screen will be completely black with no means of making it brighter. To fix this one needs to create and add the following to /etc/pm/sleep.d/restore_brightness:

#!/bin/bash
case "$1" in
   suspend|hibernate)
      #do nothing
   ;;
   resume|thaw)
      echo 7 > /sys/class/backlight/toshiba/brightness
   ;;
   *)
      exit 1
   ;;
esac
exit 0

Don't forget to chmod +x the script. You should now have a trouble free laptop :)

But I have a problem that does not work control even in the power manager.

After suspend it's ok:
lybin-R730 lybin # ls /sys/class/backlight/acpi_video0/
actual_brightness  bl_power  brightness  device  max_brightness  power  subsystem  type  uevent

(In reply to comment #12)
Well, it doesn't work even after shutdown or restart, not only after suspend, so that guess is off the table.

Also, everything works with KDE/nvidia-304.51, but doesn't with KDE/nvidia-304.60 and 304.64.
It *could* be nvidia bug, but users of other DE report everything works just fine, so this must be a matter of how KDE works with newer nvidia versions.

(In addition to comment #14)
When I say everything works with KDE/nvidia-304.51, I mean everything works *without* kernel hacks or lousy scripts.

I had a problem when the updated xorg, in gnome 3.4 do not work Fn Key.
Maybe this is the problem? In GNOME 3.6 fixed.

==> Package upgrade only (new release):
extra/xf86-input-evdev 2.7.3-1 1 -> 2
extra/xf86-input-synaptics 1.6.2-1 1 -> 2

==> Software upgrade (new version) :
extra/xorg-server-common 1.12.4-1 -> 1.13.0-2
extra/xorg-server 1.12.4-1 -> 1.13.0-2

This has nothing to do with the Fn keys. The Fn keys presses are detected fine, but KDE's PowerDevil fails to set the backlight. It does not matter whether you use Fn keys or the slider in the battery widget. Perhaps this bug would better be reported to PowerDevil maintainers?

In PowerDevil too, most likely you are right. Thx

https://bugs.kde.org/show_bug.cgi?id=296403

(In reply to comment #17)
> This has nothing to do with the Fn keys. The Fn keys presses are detected
> fine, but KDE's PowerDevil fails to set the backlight. It does not matter
> whether you use Fn keys or the slider in the battery widget. Perhaps this
> bug would better be reported to PowerDevil maintainers?

Maybe my bug is a bit different to yours, but when my fn-f6 and fn-f7 don't work, slider in battery widget - does. 

And, keys sometimes works, sometimes not.

(In reply to comment #20)
> (In reply to comment #17)
> > This has nothing to do with the Fn keys. The Fn keys presses are detected
> > fine, but KDE's PowerDevil fails to set the backlight. It does not matter
> > whether you use Fn keys or the slider in the battery widget. Perhaps this
> > bug would better be reported to PowerDevil maintainers?
> 
> Maybe my bug is a bit different to yours, but when my fn-f6 and fn-f7 don't
> work, slider in battery widget - does. 

To make it perfectly clear, for me it "works" like this. Moving the slider in the battery widget brings up the backlight percentage indicator, but the backlight intensity does not change. Pressing the Fn buttons does not even bring up the indicator, but as far as I can tell from the acpi_listen the keypresses are being registered.

(In reply to comment #21)
> (In reply to comment #20)
> > (In reply to comment #17)
> > > This has nothing to do with the Fn keys. The Fn keys presses are detected
> > > fine, but KDE's PowerDevil fails to set the backlight. It does not matter
> > > whether you use Fn keys or the slider in the battery widget. Perhaps this
> > > bug would better be reported to PowerDevil maintainers?
> > 
> > Maybe my bug is a bit different to yours, but when my fn-f6 and fn-f7 don't
> > work, slider in battery widget - does. 
> 
> To make it perfectly clear, for me it "works" like this. Moving the slider
> in the battery widget brings up the backlight percentage indicator, but the
> backlight intensity does not change. 

So my case is different. When I move the slider - indicator brings up and backlight really changes.  But on battery - it's often returns to base (20%?) value in few seconds (in indicator, and in real). 

And now when I'm writing it, keys works. Yesterday - they didn't.

(In reply to comment #17)
> This has nothing to do with the Fn keys. The Fn keys presses are detected
> fine, but KDE's PowerDevil fails to set the backlight. It does not matter
> whether you use Fn keys or the slider in the battery widget. Perhaps this
> bug would better be reported to PowerDevil maintainers?

The key combiations are not detected here.  If I run xev in a terminal and press FN+F2 or FN+F3 (the brightness controls on my Toshiba Satellite C870) I get no response.  The FN key combinations for volume control do give a keycode response.

It looks as if there is an X11 problem as well as a KDE problem.

Russell

For me on KDE 4.10 beta 2 the Fn keys work: the brightness bar appears but after a few presses on the Fn keys the bar goes crazy and stays, trying to fix a value. The percentage value changes from 60 to 70 and the slider moves accordingly.

Not sure what the bug should be considering you guys run 4.9 (and me 4.10 beta) and the problems addressed in this report are various.

I still experience this issue with KDE 4.10 beta 2. There has been no change in behavior since I first observed the bug. I'm currently on kernel 3.6.5 and nvidia drivers 310.19.

I have a slightly different issue. I am not sure if its related. My brightness keys work, but KDE does not realize that the brightness is changing, so no slider pops up. KDE also has no control over the brightness itself, so different battery profiles have no effect on the brightness. I am running Kubuntu KDE 4.10 RC2 with Nvidia 310.19.

The Xorg config option "RegistryDwords" "EnableBrightnessControl=1" used to work for me in previous versions of kde, but it does not work anymore with RC2.

Benjamin: I have the same issue, but I believe it's because the brightness is not changed at all. I don't know exactly how it works inside, but I think the popup only shows up, if kde thinks the brightness have changed and not when you press the keys. But again, I'm just guessing.

*** Bug 309106 has been marked as a duplicate of this bug. ***

Same thing here on a Samsung N150 Netbook Kubuntu 12.04 KDE 4.10.00 32 bit
I have this Notebook since kubuntu 11.10 

I was first affected by the brightness going crazy (keep going up and down) bug288852
This bug is still confirmed, although for unknown reasons it disappeared for me
This prevented me from touching brightness from november 2011 to ~ march 2012

Brightness control then went good. I then upgrade to 12.04 and upgrading kde regularly as well as kernel as soon as they get proposed by the update manager

I am affected by this bug243108 since november 2012.
Out of 17 month using kde, it is 10 month without brightness control.

This bug seems to be a complicated one, it ha been around for about 2 years (I believe it is also related to  bug243108), and I don't expect brightness control to be solved within the next 2 or 3 years, also I would like to make the following suggestion

From what I understand, problem is due to interaction between kde/bios/.
As bios control appear to handle well the brightness, is it possible as a workaround, to simply switch off every operations that kde try to carry out when fn +brightness up/down keys are being pressed? (and let the bios act alone ?)

If it is not yet possible, is it thinkable to develop it for the next kde release ? ( I mean just a quick option that let you switch off the kde brightness control ?)

Thanks

@Anne-Marie Mahfouf "the bar goes crazy" : you mean like bug288852 ?

Everything workes fine here finally with kernel 3.8.5, nvidia 313.30 and kde sc 4.10.2 on archlinux.

This bug has become a little mess, I don't think we can continue with it and be productive. 

We've got some people that got it working, some don't, the original reporter says that it is working some times... We are clearly facing different issues here.

So, I'm going to close this bug, but PLEASE each of you still affected by this bug test if you can reproduce it with 4.11 (use a livecd/usb), and if so open a new bug.

It is important to test with 4.11 before creating a new bug, we modified a bunch of things for that release that might have fixed your issue.

Thanks ! we really appreciate all the feedback.

@Alex

I am running the new KDE 4.11, but KDE still does not "realize" when I use my laptops brightness fn keys to change the brightness. The brightness will change but KDE doesn't realize it has changed and still shows the old brightness. Its a system76 lemur ultra and I'm usning the latest kernel 3.8. Should I report a new bug for this?

It works totally fine in gnome and XFCE, its only KDE that does this to me. It does it in 4.8, 4.10, and 4.11 on this laptop.

Yeah I think this is the wrong bug, because KDE can change my brightness (the automatic brightess changing works), its just that kde doesn't realize any change when I use my fn key. Will report new bug, sorry for the noise!