CrunchBang Linux

cenzo188

Member

Registered: 2013-01-26

Posts: 40

A couple of questions: Backlight and DisplayPort.

A long-time annoyance for me was the inability to control my backlight brightness effectively. Several weeks ago when I reinstalled Crunchbang I was now able to control it with the hotkeys on my keyboard, which is nice. But when running on battery, it's unstable. When I am looking at a screen that's brighter, the brightness increases. When I switch to a screen that's dimmer, the brightness decreases. You know, the exact opposite of what I'd want it to do. I'm not sure what is responsible for controlling this brightness, there's nothing I can find in power-manager.

In addition, my computer has a DisplayPort output that I use with an HDMI adapter to connect to a TV. Whenever I plug the cable in, it automatically clones my display onto the TV. I don't want that, I want to manage it manually. I've got scripts already set up to do that. That's been going on a while, it started when I installed the AMD Catalyst 13.9 drivers. There's no setting in the Catalyst control center that seems to be responsible for detecting the DisplayPort connection and automatically activating it.

The computer in question is an HP Elitebook 8560p.
So, any idea what might be responsible for automatically controlling those things?

Edit: Might be important to add: This laptop does have an ambient light sensor, which I remember on the original Windows 7 could vary the screen brightness automatically in response to light in the room. But when I shine a flashlight directly into it, or cover it with tape, I see no change in the screen brightness at all. So I don't think it's related.

Last edited by cenzo188 (2014-02-27 02:00:57)

xero

#! Junkie

From: 0x000000

Registered: 2013-09-30

Posts: 380

Website

Re: A couple of questions: Backlight and DisplayPort.

as far as screen mirroring issues use:

xrandr

or the gui version

arandr

once you have your settings the way you like them, you can setup your wm to detect the new screen and auto run your exported settings. you can use the xrandr command or use the gui to set the system up as you like then export the settings (layout > save as).

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cenzo188

Member

Registered: 2013-01-26

Posts: 40

Re: A couple of questions: Backlight and DisplayPort.

But neither xrandr or arandr have the ability to automatically switch a display when it's connected. My problem is that something, some program running in the background, is detecting that connection and automatically switching to it. So I think there must be some daemon that keeps checking xrandr for that display and then brings it up when it's connected. I want it to stop doing that, I only want it to switch displays when I use the key bindings I have set up.
So if I connect it and I don't want to output to the TV at that moment, I need to use xrandr to turn it off. It never did this until I installed the Catalyst stuff but from what I can see, there's no setting for it in the catalyst control center. It does not automatically output to VGA when that's plugged in, so it must be something unique to the DisplayPort output.

xero

#! Junkie

From: 0x000000

Registered: 2013-09-30

Posts: 380

Website

Re: A couple of questions: Backlight and DisplayPort.

if it's an ATI specific issue maybe this will help...
https://wiki.archlinux.org/index.php/AT … Head_setup

there are a few posts on the forums already about detecting a newly connect monitor. this one looks promising.

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