Xfce is always setting brightness to 100% at start

[tigrezno]

I want Xorg to start with a brightness setting of 0.5.

I've succeded at configuring lightdm in /etc/lightdm/lightdm.conf with the display-setup-script directive.

But I have failed to configure Xfce. I've tried launching the brightness script from the Session & Startup settings but didn't work.
Also tried /etc/X11/Xsession.d/ without success.

The script actually executed but something else is setting the brightness again at 100% after that.

I'm so mad at it that I'm on the verge to uninstall xfce and use other DE.

[note] I'm using xrandr since xbacklight doesn't work. I'm on a desktop PC.

[SOLVED] Somehow. I just added a .desktop file with the script in ~/.config/autostart. It's executed AFTER xfce sets the brightness to 100%, so it works. For a few milliseconds there is a flash, but that's all.

[EDIT] Ok, I found the real culprit. It was nvidia-settings being loaded by xfce. I had to set the brightness in the nvidia-settings GUI. That fixed the issue.

[yetimon_64]

...
I'm so mad at it that I'm on the verge to uninstall xfce and use other DE.

[note] I'm using xrandr since xbacklight doesn't work. I'm on a desktop PC.

I have bolded the last comment in your post. It stood out the most here on reading the post.

On a desktop PC that situation actually sounds right. I have never known of a desktop pc that didn't set the brightness at 100% all the time.
I have only ever seen the screen brightness lowered in xfce on laptops, never on a desktop installation of xfce here and I've had a few on each type of system.

If you are on a desktop, usually that would indicate a monitor plugged in via either a VGA or HDMI cable. Most external monitors I've ever seen or used require the brightness to be set in the monitor's menu itself, either via a remote control or buttons on the monitor itself, NOT from the OS or DE as it sounds like you are trying to do.

If you really are trying this on a desktop PC with a normal monitor and not on a laptop you seem to be trying to set up an impossible situation (and poor ol' xfce is copping the blame ). Cheers, yeti.

[The Cog]

I use redshift to alter the colour of my monitor in the evenings, it that helps at all.