The task is to join 6 monitors with 2 VGA cards and built in adapter in Gnome 3.8
Here is a list of VGA adapters:
02:00.0 VGA compatible controller: NVIDIA Corporation GP104 [GeForce GTX 1070] (rev a1)
03:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Caicos [Radeon HD 6450/7450/8450 / R5 230 OEM]
08:00.0 VGA compatible controller: ASPEED Technology, Inc. ASPEED Graphics Family (rev 30).
xorg.conf was balanced after time and all monitors are up. Multiple VGA cards are not working out of the box. Each adapter works separately with this config if to place screen based adapters one by one to ServerLayout section. I present xorg.conf file and links to materials that helped to make it work for community. This config detects all connected to NVIDIA card monitors can be controlled by Gnome. All other monitors stay blank, but mouse pointer of x server style (X sign) can be moved and seen on other monitors.
Section "OutputClass"
Identifier "nvidia"
MatchDriver "nvidia-drm"
Driver "nvidia"
Option "AllowEmptyInitialConfiguration"
Option "SLI" "Auto"
Option "BaseMosaic" "on"
Option "PrimaryGPU"
EndSection
Section "OutputClass"
Identifier "ati"
MatchDriver "radeon"
Driver "radeon"
EndSection
Section "ServerLayout"
Identifier "Layout0"
Screen 0 "LeftDown" 0 0
Screen 1 "RightDown" RightOf "LeftDown"
Screen 2 "RightUpper" Above "RightDown"
Screen 3 "BuiltIn" RightOf "RightDown"
Screen 4 "Portrait" RightOf "BuiltIn"
InputDevice "Keyboard0" "CoreKeyboard"
InputDevice "Mouse0" "CorePointer"
EndSection
Section "Monitor"
Identifier "SamsLeft"
VendorName "Samsung"
ModelName "Unknown"
Option "DPMS"
EndSection
Section "Monitor"
Identifier "SamsRight"
VendorName "Samsung"
ModelName "Unknown"
Option "DPMS"
EndSection
Section "Monitor"
Identifier "PhilRightUpper"
VendorName "Philips"
ModelName "24 inches"
Option "DPMS"
EndSection
Section "Monitor"
Identifier "Phil27"
VendorName "Philips"
ModelName "27 inches"
Option "DPMS"
EndSection
Section "Monitor"
Identifier "PhilPortrait"
VendorName "Philips"
ModelName "24 inches"
Option "DPMS"
EndSection
Section "Device"
Identifier "gtx"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BusID "PCI:2:0:0"
EndSection
Section "Device"
Identifier "atiradeon"
Driver "radeon"
VendorName "AMD/ATI"
BusID "PCI:3:0:0"
EndSection
Section "Device"
Identifier "builtin"
Driver "modesetting"
VendorName "Built In Video"
BusId "PCI:8:0:0"
EndSection
Section "Screen"
Identifier "LeftDown"
Device "gtx"
Monitor "SamsLeft"
Option "metamodes" "DP-0: nvidia-auto-select +0+0"
Option "SLI" "Off"
Option "MultiGPU" "Off"
Option "BaseMosaic" "off"
DefaultDepth 24
SubSection "Display"
Depth 24
EndSubSection
EndSection
Section "Screen"
Identifier "RightDown"
Device "gtx"
Monitor "SamsRight"
Option "metamodes" "DP-2: nvidia-auto-select +0+0"
Option "SLI" "Off"
Option "MultiGPU" "Off"
Option "BaseMosaic" "off"
DefaultDepth 24
SubSection "Display"
Depth 24
EndSubSection
EndSection
Section "Screen"
Identifier "RightUpper"
Device "gtx"
Monitor "PhilRightUpper"
Option "metamodes" "HDMI-0: nvidia-auto-select +0+0"
Option "SLI" "Off"
Option "MultiGPU" "Off"
Option "BaseMosaic" "off"
DefaultDepth 24
SubSection "Display"
Depth 24
EndSubSection
EndSection
Section "Screen"
Identifier "Portrait"
Device "atiradeon"
Monitor "PhilPortrait"
DefaultDepth 24
SubSection "Display"
Depth 24
EndSubSection
EndSection
Section "Screen"
Identifier "BuiltIn"
Device "builtin"
Monitor "Phil27"
DefaultDepth 24
SubSection "Display"
Depth 24
EndSubSection
EndSection
But xrandr shows each VGA card as separate screen. Moreover, each non-primary screen (screen 0 display) can be pointed by mouse with cross on it.
$ xrandr --listproviders
Providers: number : 1
Provider 0: id: 0x1b8 cap: 0x1, Source Output crtcs: 4 outputs: 8 associated providers: 0 name:NVIDIA-0
$ xrandr --screen 1 --listproviders
Providers: number : 1
Provider 0: id: 0x1f9 cap: 0x0 crtcs: 1 outputs: 1 associated providers: 0 name:modesetting
$ xrandr --screen 2 --listproviders
Providers: number : 1
Provider 0: id: 0x232 cap: 0xf, Source Output, Sink Output, Source Offload, Sink Offload crtcs: 4 outputs: 3 associated providers: 0 name:CAICOS @ pci:0000:03:00.0
xrandr shows all connected monitors properly, but they are separated by screens and not listed by gnome. It is possible to run xterm, for instance on this unlisted monitors, however input like keyboard is impossible:
DISPLAY=:1.1 xterm &
DISPLAY=:1.2 xterm &
Seems that it is misconfiguration somewhere. Is it possible add these screens to primary gnome session or join displays into one somehow?
