Powerdevil bug help needed

[Ongun Kanat]

Hello devs,

I'm trying to contribute by fixing a small bug. I'm proficient with
C++ and pretty much used to debug C++ programs with Qt Creator. I've
managed to build full plasma desktop into a directory in my home using
kdesrc-build. and set environment correctly  Now I can launch latest
git version of plasma.

I'm trying to fix a bug in Powerdevil (as i guess):
https://bugs.kde.org/show_bug.cgi?id=371915
It looks like a calculation error is being made somewhere but I
couldn't trigger any breakpoint in powerdevil executable. Moreover on
git version of plasma it seems like powerdevil is not be able to get
any sort of brightness signal at all and the kernel's/framebuffer's
standard brightness functionality seems to be triggered. I'm making
this guess since the brightness notification is not being shown. On my
distro's (Arch, pretty vanilla) version of plasma both notification
and powerdevil works and xev displays brightness buttons correctly.

Wandering the installed files in my build directory, I realized kdesrc
have installed dbus-1/system-services folder into the install
directory in my home directory as expected. And there's a dbus service
file called org.kde.powerdevil.backlighthelper.service . I think this
file doesn't get started since it's not in the real /usr/share/dbus-1
folder. Instead the distro's version of it gets started which is
incompatible and is not a part of my git build. Hence, no backlight
signal has been gotten caught and transferred to org.kde.powerdevil
service.

So, my questions are:
- Is my reasoning correct?
- If it's, is there any clean way to force dbus to launch the files in
my build directory instead of /usr. Using an environment variable
would be nice
- If it's not possible what are your ways to debug/replace dbus system
services like powerdevil's one?


Thanks,
-Ongun

PS: It can be understood but in any case of need, my build directory
is located at: /home/ongun/kde/usr .