The holy grail fix for me last night was: Base Mosaic! Empty xorg.conf, nvidia x server settings-> Enable Base Mosaic, then enable each detected display. It all just works! fast seemless multi-gpu, multi-head multi-monitor setup with 1 xscreen ! My 3 displays are different resolutions and one is rotated portrait. Even the ubuntu Settings - Displays correctly shows all 3 monitors.
-chad
➜ ~ nvidia-xconfig --query-gpu-info
Number of GPUs: 2 GPU #0: Name : GeForce 9800 GT UUID : GPU-56281125-01c7-ee85-b8b9-b3e5cf94b7c5 PCI BusID : PCI:1:0:0 Number of Display Devices: 1 Display Device 0 (CRT-0): EDID Name : Samsung SyncMaster Minimum HorizSync : 30.000 kHz Maximum HorizSync : 81.000 kHz Minimum VertRefresh : 56 Hz Maximum VertRefresh : 75 Hz Maximum PixelClock : 146.250 MHz Maximum Width : 1680 pixels Maximum Height : 1050 pixels Preferred Width : 1680 pixels Preferred Height : 1050 pixels Preferred VertRefresh : 60 Hz Physical Width : 470 mm Physical Height : 300 mm GPU #1: Name : GeForce 9800 GT UUID : GPU-cbc59e3f-e8c1-a347-a069-b62f6b885f7d PCI BusID : PCI:2:0:0 Number of Display Devices: 2 Display Device 0 (CRT-0): EDID Name : Samsung SyncMaster Minimum HorizSync : 30.000 kHz Maximum HorizSync : 81.000 kHz Minimum VertRefresh : 56 Hz Maximum VertRefresh : 75 Hz Maximum PixelClock : 140.000 MHz Maximum Width : 1280 pixels Maximum Height : 1024 pixels Preferred Width : 1440 pixels Preferred Height : 900 pixels Preferred VertRefresh : 60 Hz Physical Width : 410 mm Physical Height : 270 mm Display Device 1 (DFP-1): EDID Name : Ancor Communications Inc ASUS VH242H Minimum HorizSync : 30.000 kHz Maximum HorizSync : 85.000 kHz Minimum VertRefresh : 55 Hz Maximum VertRefresh : 75 Hz Maximum PixelClock : 160.000 MHz Maximum Width : 1920 pixels Maximum Height : 1080 pixels Preferred Width : 1920 pixels Preferred Height : 1080 pixels Preferred VertRefresh : 60 Hz Physical Width : 520 mm Physical Height : 290 mm Below is my xorg.conf - All of which x server settings generated. Note that it is quite straight forward, and does not even reference my second GPU.
# nvidia-settings: X configuration file generated by nvidia-settings # nvidia-settings: version 331.20 (buildd@roseapple) Mon Feb 3 15:07:22 UTC 2014 Section "ServerLayout" Identifier "Layout0" Screen 0 "Screen0" 0 0 InputDevice "Keyboard0" "CoreKeyboard" InputDevice "Mouse0" "CorePointer" Option "Xinerama" "0" EndSection Section "Files" EndSection Section "InputDevice" # generated from default Identifier "Mouse0" Driver "mouse" Option "Protocol" "auto" Option "Device" "/dev/psaux" Option "Emulate3Buttons" "no" Option "ZAxisMapping" "4 5" EndSection Section "InputDevice" # generated from default Identifier "Keyboard0" Driver "kbd" EndSection Section "Monitor" # HorizSync source: edid, VertRefresh source: edid Identifier "Monitor0" VendorName "Unknown" ModelName "Samsung SyncMaster" HorizSync 30.0 - 81.0 VertRefresh 56.0 - 75.0 Option "DPMS" EndSection Section "Device" Identifier "Device0" Driver "nvidia" VendorName "NVIDIA Corporation" BoardName "GeForce 9800 GT" BusID "PCI:1:0:0" EndSection Section "Screen" auto-select +3600+0 {rotation=right}, GPU-cbc59e3f-e8c1-a347-a069-b62f6b885f7d.GPU-1.DVI-I-3: nvidia-auto-select +1680+180" Identifier "Screen0" Device "Device0" Monitor "Monitor0" DefaultDepth 24 Option "Stereo" "0" Option "nvidiaXineramaInfoOrder" "CRT-0" Option "metamodes" "GPU-56281125-01c7-ee85-b8b9-b3e5cf94b7c5.GPU-0.DVI-I-0: nvidia-auto-select +0+180, GPU-cbc59e3f-e8c1-a347-a069-b62f6b885f7d.GPU-1.DVI-I-0: nvidia-auto-select +3600+0 {rotation=right}, GPU-cbc59e3f-e8c1-a347-a069-b62f6b885f7d.GPU-1.DVI-I-3: nvidia-auto-select +1680+180" Option "MultiGPU" "Off" Option "SLI" "off" Option "BaseMosaic" "on" SubSection "Display" Depth 24 EndSubSection EndSection