amd gpu but display on intel integrated graphics

On my Ubuntu 12.04 I connected my monitor to the onboard intel graphics. I'd like to use my ati radeon 6770 for opencl tasks (e.g. bitcoin mining).

So far I couldn't figure out how to get the ati driver working. When calling "aticonfig --initial -f" it always writes a new xorg.conf that ignores the intel graphics. At boot time it works only when I attached the monitor to the ati card.

So I manually tampered with the xorg.conf and got this:

Section "ServerLayout"
    Identifier     "Default Monitor"
    Screen      0  "myscreen" 0 0
    Screen      1  "deadscreen" RightOf "myscreen"
EndSection

Section "Module"
EndSection

Section "Monitor"
    Identifier "Default Monitor"
    Option "VendorName" "Monitor Vendor"
    Option "ModelName" "Monitor Name"
    Option "DPMS" "true"
EndSection

Section "Monitor"
    Identifier "null Monitor"
    Option         "Enable" "false"
EndSection

Section "Device"
    Identifier "Intel Integrated Graphics"
    Driver     "intel"
    BusID      "PCI:0:2:0"
    Screen 0
EndSection

Section "Device"
    Identifier  "aticonfig-Device[0]-0"
    Driver      "fglrx"
    BusID       "PCI:1:0:0"
    Screen 1
EndSection

Section "Screen"
    Identifier "myscreen"
    Device     "Intel Integrated Graphics"
    Monitor    "Default Monitor"
    DefaultDepth     24
    SubSection "Display"
        Viewport   0 0
        Depth     24
    EndSubSection
EndSection

Section "Screen"
    Identifier "deadscreen"
    Device     "aticonfig-Device[0]-0"
    Monitor    "null Monitor"
    DefaultDepth     24
    SubSection "Display"
        Viewport   0 0
        Depth     24
    EndSubSection
EndSection

I think this might be the right way since I see that X tries to start both drivers in /var/log/Xorg.0.log. However the fglrx driver seems crash (end of xorg.0.log):

Backtrace:
[     6.625] 0: /usr/bin/X (xorg_backtrace+0x26) [0x7fb5cd41b846]
[     6.625] 1: /usr/bin/X (0x7fb5cd293000+0x18c6ea) [0x7fb5cd41f6ea]
[     6.625] 2: /lib/x86_64-linux-gnu/libpthread.so.0 (0x7fb5cc5b9000+0xfcb0) [0x7fb5cc5c8cb0]
[     6.625] 3: /usr/lib/x86_64-linux-gnu/xorg/extra-modules/extra-modules.dpkg-tmp/modules/drivers/fglrx_drv.so (xdl_xs111_atiddxGetGPUMapInfo+0x1b1) [0x7fb5c88e16b1]
[     6.625] 4: /usr/lib/x86_64-linux-gnu/xorg/extra-modules/extra-modules.dpkg-tmp/modules/drivers/fglrx_drv.so (atiddxGetGPUMapInfo+0xd) [0x7fb5c87bcc0d]
[     6.625] 5: /usr/lib/x86_64-linux-gnu/xorg/extra-modules/extra-modules.dpkg-tmp/modules/extensions/libglx.so (0x7fb5ca12d000+0x1ab29) [0x7fb5ca147b29]
[     6.625] 6: /usr/lib/x86_64-linux-gnu/xorg/extra-modules/extra-modules.dpkg-tmp/modules/extensions/libglx.so (0x7fb5ca12d000+0x1cf8c) [0x7fb5ca149f8c]
[     6.625] 7: /usr/lib/x86_64-linux-gnu/xorg/extra-modules/extra-modules.dpkg-tmp/modules/extensions/libglx.so (0x7fb5ca12d000+0x1ee55) [0x7fb5ca14be55]
[     6.626] 8: /usr/bin/X (InitExtensions+0x99) [0x7fb5cd350069]
[     6.626] 9: /usr/bin/X (0x7fb5cd293000+0x3d605) [0x7fb5cd2d0605]
[     6.626] 10: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xed) [0x7fb5cb44e76d]
[     6.626] 11: /usr/bin/X (0x7fb5cd293000+0x3daad) [0x7fb5cd2d0aad]
[     6.626] Segmentation fault at address 0x14
[     6.626] 
Caught signal 11 (Segmentation fault). Server aborting
[     6.626] 

I'd be very happy if someone can give me a hint on how to configure my ATI card while using the integrated graphics for display.

Update

I used most of jjhughes57 config and successfully booted the X server on intel (keyboard layout is changed though, funnily).

Unfortunately the 2nd X server (fglrx) doesn't fully start. It shuts itself down right after starting>

[     6.265] (II) fglrx(0): Restoring Recent Mode via PCS is not supported in RANDR 1.2 capable environments
[     6.296] (II) UnloadModule: "mouse"
[     6.296] (II) Unloading mouse
[     6.296] (II) UnloadModule: "kbd"
[     6.296] (II) Unloading kbd
[     6.298] (II) fglrx(0): Shutdown CMMQS
[     6.298] (II) fglrx(0): [uki] removed 1 reserved context for kernel
[     6.298] (II) fglrx(0): [uki] unmapping 8192 bytes of SAREA 0x2000 at 0x7fbef8209000
[     6.337] (II) fglrx(0): Interrupt handler Shutdown.
[     6.470]  ddxSigGiveUp: Closing log
[     6.470] Server terminated successfully (0). Closing log file.

Thanks for any hints what is wrong here.

Solution

In my case the solution was quite simple. Mainly the xorg.conf (from jjhughes57) brought me on the right track. The remaining issues could be fixed in /etc/lightdm/lightdm.conf. My final version is:

[LightDM]
seats=Seat:0 Seat:1

[SeatDefaults]
autologin-user-timeout=0
autologin-session=lightdm-autologin
greeter-session=lightdm-gtk-greeter


[Seat: 0]
xserver-layout=seat0
xserver-command=/usr/bin/X :0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -sharevts -novtswitch
autologin-guest=false
autologin-user=fx
autologin-user-timeout=0
autologin-session=lightdm-autologin
user-session=ubuntu

[Seat: 1]
xserver-layout=seat1
xserver-command=/usr/bin/X :1 -auth /var/run/lightdm/root/:1 -nolisten tcp vt8 -sharevts -novtswitch
autologin-guest=true
user-session=ubuntu

One problem was that "/usr/share/xgreeters/lightdm-gtk-greeter.desktop" was missing. After properly installing lightdm-gtk-greeter again the second X-server came up successfully. Now the following requirements need to be fulfilled:

1. X needs to accept connections on :1 (assuming that :1 is your
2. fglrx-display) your user needs permission to open X-clients on :1

Actually I first tried with autologin-guest=false which doesn't work. With autologin-guest=true and a running user session (as a guest user) you need to disable X access control (that's the easiest at least). E.g.: on display :0 as root:

# su - guest-6ht0hq
guest-6ht0hq$ echo $DISPLAY
:0.0
guest-6ht0hq$ export DISPLAY=:1
guest-6ht0hq$ xhost +
access control disabled, clients can connect from any host
guest-6ht0hq$

Now on another terminal (as root):

# DISPLAY=:1.0 aticonfig --adapter=0 --od-getclocks
Adapter 0 - AMD Radeon HD 6700 Series 
                            Core (MHz)    Memory (MHz)
           Current Clocks :    850           1000
             Current Peak :    850           1000
  Configurable Peak Range : [500-970]     [1000-1430]
                 GPU load :    0%
#