Hey there everyone,
I'm having a rather tough issue, and I've done alot of searching and couldn't find the right answer to my problem (also, please forgive me if I've posted this in the wrong forum). I have actually seen many blog posts and forum posts talking about something like this, but never found a full solution. I have an Intel Sandy Bridge machine (has Intel HD 2000 integrated graphics) with a Radeon 7770 PCI-E graphics card. I have one monitor connected to the radeon, and another connected to the intel graphics. Everything in the bios has been set up, and under Windows, Ubuntu (Trusty Tahr beta2, Ubuntu GNOME), and Fedora 20 (GNOME), both monitors are detected and correctly span without any configuration. I'm having some issues under Arch though, and things are not autodetected. Here is the lspci output for the two devices in question:
00:02.0 Display controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09) 01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Cape Verde XT [Radeon HD 7770/8760 / R7 250X]
Here is a list of what I did, and the resulting logs, and output:
1st Case: Ubuntu's Xorg.0.log
Xorg Log: http://pastebin.com/PvDfDXQA
All this is is the xorg log produced by Ubuntu for a working set of displays. It initializes the radeon and intel graphics appropriately.
2nd Case: Arch without an xorg.conf
Xorg Log: http://pastebin.com/Jtejnn3D
For this case, I had all of the xf86 packages installed (particularly xf86-video-intel, xf86-video-ati, and xf86-video-modesetting, since they were the most critical to this process). I then just had GDM run without any xorg.conf present under /etc/X11. As you can see from the log, Xorg does not initialize the intel graphics.
For this case, I autogenerated an xorg.conf file in Ubuntu, and used it under Arch. I think I used this command, but I can't remember:
sudo X :2 -configure
Believe it or not, this method had the most success, since both displays now come up. The radeon display has a blank output, and a mouse cursor (a black X, typical of Xorg being unconfigured), and a black screen screen background. The intel display has gdm and GNOME fully working. So while not fully functioning, at least the display is outputting something.
Since Case 3 produced better results, I tried to strip the xorg.conf, and enable/disable a few things based on what I have read in the arch wiki about multihead, and created something which I thought might work. Unfortunately, this xorg.conf segfaults. I attempted to fiddle with the xorg.conf, by turning off xinerama for example, or modifying some of the screens config, but I cannot seem to figure out what I am doing wrong.
So, what has my testing proven so far?
The setup I desire is certainly possible, since I can do it under Ubuntu and Fedora. It must be possible under Arch, if the other distros could get it working using auto-configuration.
Both graphics cards are capable of working under Arch, since under different xorg.conf situations, both have come up somehow or another.
I just don't know how to make xorg see both graphics cards and both monitors at the same time, as a spanned display.
In any case, any help is appreciated. I'm currently typing this from an Ubuntu installation, hoping that maybe I can move back to Arch once I get the right config .