With kernel 3.4+ the slider in the battery plasmoid has no effect on screen brightness. However, I can still change the brightness using my laptops function keys. Dell Studio XPS 1340. Nvidia proprietary driver. Reproducible: Always
Confirmed using Intel i915. When I change the brightness using my Fn keys, the slider in the popup changes its position accordingly, though.
It seems to somewhat work. When I click on the brightness slider somewhere, it works. But when I just drag the slider, then it does not really work.
Dragging the slider with the mouse does not change the brightness until you release the mouse button. When I change the brightness with my Fn keys the slider does NOT change accordingly. So I end up with the lowest brightness and the slider 100% on the right. 4.9 git master. Is it a regression?
@Anne-Marie Mahfouf: Well that the Fn keys work independently from the Battery plasmoid may be an issue with your ACPI so that Solid is not aware of the actual brightness. It used to be the same way on my notebook till I added acpi_backlight=vendor to my kernel boot parameters
OK, thanks Kai, let's forget my Fn problem. Marking as regression hence prioritizing it higher.
This bug report started drifting into being about two issues. Updating title to clarify which one, and assigning to me (who has a patch)
Git commit c449ddccc87f3633aff6f34b161a31a7293cde32 by David Edmundson. Committed on 13/06/2012 at 23:41. Pushed by davidedmundson into branch 'master'. fix a bug where the value would not be changed whilst dragging, only when released. Fixes reported issues in battery applet REVIEW: 105236 M +0 -1 plasma/declarativeimports/plasmacomponents/qml/Slider.qml http://commits.kde.org/kde-runtime/c449ddccc87f3633aff6f34b161a31a7293cde32
The original bug I reported still exists- I never had the problem fixed by review 105236. The slider has no effect on screen brightness, only the function keys or automatic power management can change it.
Never mind. Just upgraded to kernel 3.4.4-2-ARCH and it's working normally again!