Multiple X server, one GPU, two outputs

[MartjeB]

Hello,
Right now I have two cards in my computer. A Radeon HD3870 and a GeForce 8400GS. I can start two seperate X-servers by executing:

Xorg -layout seat0
Xorg -layout seat1

There's no problem there. My actual question is: since the Radeon HD3870 is a dualhead card (ie. Multiple outputs, 2x DVI), could I start seperate X-servers on both outputs (with OSS drivers)? I know I can achieve this with Xephyr, but I don't want to rely on that.

This way I can remove the Nvidia card and save some power consumed by it.

Edit: Woops, this should be in 'X.Org & Mesa', shouldn't it?

[agd5f]

The radeon driver supports the older zaphod style of dualhead, but it doesn't get tested much so YMMV.

[MartjeB]

From what I read, the zaphod method is something like this:

Section "Serverflags"
	Option	"Dontzap"	"no"
	Option	"AutoAddDevices"	"false"
	Option  "AllowMouseOpenFail"    "true"
EndSection

Section "ServerLayout"
        Identifier     "seat0"
        Screen      0  "Screen0" 0 0
        InputDevice    "Mouse0" "CorePointer"
        InputDevice    "Keyboard0" "CoreKeyboard"
EndSection

Section "ServerLayout"
        Identifier     "seat1"
        Screen      0  "Screen1" 0 0
        InputDevice    "Mouse1" "CorePointer"
        InputDevice    "Keyboard1" "CoreKeyboard"
EndSection

Section "Monitor"
	Identifier	"Samsung T200 (0)"
EndSection

Section "Monitor"
	Identifier	"Samsung T200 (1)"
EndSection

Section "Device"
	Identifier	"Radeon HD3870 (0)"
	BusID		"PCI:1:0:0"
	Driver		"radeonhd"
	Screen		0
EndSection

Section "Device"
	Identifier	"Radeon HD3870 (1)"
	BusID		"PCI:1:0:0"
	Driver		"radeonhd"
	Screen		1
EndSection

Section "Screen"
	Identifier	"Screen0"
	Monitor		"Samsung T200 (0)"
	Device		"Radeon HD3870 (0)"
EndSection

Section "Screen"
	Identifier	"Screen1"
	Monitor		"Samsung T200 (1)"
	Device		"Radeon HD3870 (1)"
EndSection

Section "InputDevice"
        Identifier	"keyboard0"
        Driver	"evdev"
        Option	"Device"	"/dev/input/by-path/pci-0000:00:12.1-usb-0:1:1.0-event-kbd"
        Option	"XkbModel"	"evdev"
        Option	"XkbLayout"	"us"
EndSection

Section "InputDevice"
	Identifier	"Mouse0"
	Driver	"evdev"
	Option	"Protocol" "ExplorerPS/2"
	Option	"Device" "/dev/input/by-path/pci-0000:00:12.0-usb-0:3:1.0-event-mouse"
EndSection

Section "InputDevice"
        Identifier      "keyboard1"
        Driver          "evdev"
        Option          "Device"                "/dev/input/by-path/pci-0000:00:12.0-usb-0:2:1.0-event-kbd"
        Option          "XkbModel"              "evdev"
        Option          "XkbLayout"             "us"
EndSection

Section "InputDevice"
	Identifier	"Mouse1"
	Driver	"evdev"
	Option	"Protocol" "ExplorerPS/2"
	Option	"Device" "/dev/input/by-path/platform-i8042-serio-1-event-mouse"
EndSection

Am I right?

[agd5f]

yes, that's correct.

[MartjeB]

It doesn't work unfortunately:

Xorg.1.log

[    0.064357] (EE) Screen 0 deleted because of no matching config section.
[    0.064372] (II) UnloadModule: "radeon"
[    0.064377] (EE) Device(s) detected, but none match those in the config file.

Fatal server error:
no screens found

Please consult the The X.Org Foundation support 
	 at http://wiki.x.org
 for help. 
Please also check the log file at "/var/log/Xorg.1.log" for additional information.

 ddxSigGiveUp: Closing log

Exact the same thing with radeonhd. Xephyr here I come

[Blue Beard]

I found this Debian howto informative why some of the old configuration methods don't work:

http://wiki.debian.org/XStrikeForce/HowToRandR12

What I would like to find, is what is xrandr's design directions for future items.