Bug 399018

Summary:	No brightness control on NVIDIA
Product:	[Unmaintained] Powerdevil	Reporter:	Gabriel Souza Franco <gabrielfrancosouza>
Component:	general	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	RESOLVED FIXED
Severity:	normal	CC:	bshah, kde
Priority:	NOR
Version First Reported In:	5.13.90
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:	https://commits.kde.org/powerdevil/6b93d74675aeb8f6fad26f62f300e4ed6b155ad4	Version Fixed/Implemented In:
Sentry Crash Report:

Description Gabriel Souza Franco 2018-09-24 13:56:32 UTC

SUMMARY
Since the removal of the XRandR backend in Powerdevil (https://phabricator.kde.org/D15261), KDE cannot control my laptop brightness anymore. I already tried all /sys/class/backlight devices, and all values for the acpi_backlight kernel parameter. XRandR works because it calls directly into the NVIDIA driver, as far as I know.

SOFTWARE VERSIONS
KDE Plasma Version: 5.13.90
KDE Frameworks Version: 5.50
Qt Version: 5.11.2

Comment 1 Kai Uwe Broulik 2018-09-24 13:57:44 UTC

I think easiest would just be to revert the offending commit, given it was the only change in PowerDevil this cycle, should be pretty safe?

Comment 2 Bhushan Shah 2018-09-24 14:11:17 UTC

Hmm, can you list all the sysfs interfaces you have?

Comment 3 Gabriel Souza Franco 2018-09-24 14:49:13 UTC

$ ls /sys/class/backlight
acpi_video0

If I boot with acpi_backlight=vendor, then I have:
$ ls /sys/class/backlight
ideapad

Neither of those work.

Comment 4 Kai Uwe Broulik 2018-09-25 13:58:50 UTC

Git commit 6b93d74675aeb8f6fad26f62f300e4ed6b155ad4 by Kai Uwe Broulik.
Committed on 25/09/2018 at 13:57.
Pushed by broulik into branch 'Plasma/5.14'.

Revert "Remove XRandrBrightness"

Apparently there's still graphics cards that rely on this :'(

This was the only real change in this cycle, so just reverting it is safe,
albeit technically being a dependency change.
CCMAIL: kde-distro-packagers@kde.org

This reverts commit 7e29869329184d9e2bae6019939e2ecb0eceac0d.

M  +1    -1    CMakeLists.txt
M  +6    -1    daemon/backends/CMakeLists.txt
M  +113  -59   daemon/backends/upower/powerdevilupowerbackend.cpp
M  +4    -0    daemon/backends/upower/powerdevilupowerbackend.h
A  +221  -0    daemon/backends/upower/xrandrbrightness.cpp     [License: LGPL (v2)]
A  +51   -0    daemon/backends/upower/xrandrbrightness.h     [License: LGPL (v2)]
A  +124  -0    daemon/backends/upower/xrandrxcbhelper.cpp     [License: GPL (v2+)]
A  +99   -0    daemon/backends/upower/xrandrxcbhelper.h     [License: GPL (v2+)]

https://commits.kde.org/powerdevil/6b93d74675aeb8f6fad26f62f300e4ed6b155ad4