HOWTO Multiseat X

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A multiseat, multi-station or multiterminal configuration is a single computer which supports multiple users at the same time. The configuration typically consist of one monitor, keyboard and mouse for each user.

Contents

[edit] Requirements

  • multiple graphic cards (or a dual head one providing multiple PCI adresses) (if you have a single address multi head card, you might be interested in projects around Xnest / Xephyr)
  • multiple keyboards and mice (USB; exept one keyboard and one mouse can be PS/2)
  • recent kernel (I use 2.6.18, but any >=2.6.12 should work)
  • udev
  • hotplug
  • pciutils
  • Xorg: at least version 6.9 / 7.0

[edit] X configuration

[edit] know thy devices

  • Run lspci to get the PCI addresses of your graphic cards.
  • Read the file /proc/bus/input/devices to get the addresses of your input devices.
    • Remember the kdb eventX indicating the /dev/input/eventX keyboard input device
    • and mouseX eventY indicating the /dev/input/mouseX the mouse input device

[edit] Writing the configuration - xorg.conf

You need to write or adapt your /etc/X11/xorg.conf:

File: /etc/X11/xorg.conf 
### General Sections ###
Section "ServerFlags"
        Option "DefaultServerLayout" "alltogether"
        Option "AllowMouseOpenFail"  "true"
        Option "AIGLX" "true"   ### want AIGLX so put it here
EndSection

Section "ServerLayout"
        Identifier     "alltogether"
        Screen      0  "Screen0" 0 0
        ....
        Screen      N  "ScreenN" RightOf "ScreenN-1"
        InputDevice    "Mouse0" "CorePointer"
        ....
        InputDevice    "MouseN" "CorePointer"
        InputDevice    "Keyboard0" "CoreKeyboard"
        ....
        InputDevice    "KeyboardN" "CoreKeyboard"
EndSection

Section "Files"
        RgbPath      "/usr/X11R6/lib/X11/rgb"
        FontPath     "/usr/share/fonts/corefonts"     ### fonts according your system
        FontPath     "/usr/share/fonts/TrueType"
        FontPath     "/usr/share/fonts/misc"
EndSection

Section "Module"
        Load  "dbe"            ### modules according to your system / graphic cards
        Load  "extmod"
        Load  "fbdevhw"
        Load  "glx"
        Load  "record"
        Load  "freetype"
        Load  "type1"
        Load  "dri"
EndSection

Section "DRI"
        Mode         0666
EndSection

### One of these sections per seat ###

Section "ServerLayout"
        Identifier     "seatX"
        Screen      X  "ScreenX" 0 0
        InputDevice    "MouseX" "CorePointer"
        InputDevice    "KeyboardX" "CoreKeyboard"
EndSection

Section "InputDevice"
        Identifier  "KeyboardX"
        Driver      "evdev"
        Option      "Device" "/dev/input/eventX"    ### event device according to /proc/bus/input/devices
        Option      "XkbModel" "evdev"
        Option      "XkbLayout" "us"   ### Language setting
EndSection

Section "InputDevice"
        Identifier  "MouseX"
        Driver      "mouse"
        Option      "Protocol" "IMPS/2"
        Option      "Device" "/dev/input/mouseX"   ### mouse device according to /proc/bus/input/devices
        Option      "ZAxisMapping" "4 5"   ### Wheel mouse
EndSection

Section "Screen"
        Identifier "ScreenX"
        Device     "VideocardX"
        Monitor    "MonitorX"
        DefaultDepth     24
        SubSection "Display"
                Depth     24
                Modes    "1280x1024" "1024x768" "800x600"
        EndSubSection
EndSection

Section "Device"
        Identifier  "VideocardX"
        Driver      "nvidia"   ### or whatever driver you use
        BusID       "PCI:x:y:z"   ### PCI bus address (in decimal) according to 'lspci' (which is in hex)
EndSection

Section "Monitor"
        Identifier   "MonitorX"
        Option      "dpms"
EndSection

[edit] Multimedia Keyboards

Some multimedia keyboards, like for example the "Logitech UltraX media keyboard" or the "Microsoft Natural Keyboard Pro", will register it self as two devices in /proc/bus/input/devices:

File: /proc/bus/input/devices 
I: Bus=0003 Vendor=045e Product=001d Version=0114
N: Name="Microsoft Natural Keyboard Pro"
P: Phys=usb-0000:00:07.4-1.4.1/input0
S: Sysfs=/class/input/input0
H: Handlers=kbd event0
B: EV=120003
B: KEY=10000 7 ff800000 7ff febeffdf f3cfffff ffffffff fffffffe
B: LED=7

I: Bus=0003 Vendor=045e Product=001d Version=0114
N: Name="Microsoft Natural Keyboard Pro"
P: Phys=usb-0000:00:07.4-1.4.1/input1
S: Sysfs=/class/input/input1
H: Handlers=kbd event1
B: EV=f
B: KEY=c0002 400 0 0 1 c00 78000 2639fa d841d7ad 9e0000 0 0 0
B: REL=40
B: ABS=1 0

To get this to work two InputDevice has to be created in xorg.conf:

File: /etc/X11/xorg.conf 
Section "InputDevice"
        Identifier  "KeyboardX:1"
        Driver      "evdev"
        Option      "Phys"   "usb-*/input0"    ### matches event device phys string according to /proc/bus/input/devices
        Option      "evBits"  "+1"
        Option      "keyBits" "~1-255 ~352-511"
        Option      "Pass"    "3"      ### Scan Order
        Option      "XkbLayout" "se"   ### Language setting
EndSection

Section "InputDevice"
        Identifier  "KeyboardX:2"
        Driver      "evdev"
        Option      "Phys"   "usb-*/input1"    ### matches event device phys string according to /proc/bus/input/devices
        Option      "evBits"  "+1"
        Option      "keyBits" "~1-255 ~352-511"
        Option      "Pass"    "3"      ### Scan Order
        Option      "XkbLayout" "se"   ### Language setting
EndSection

Section "ServerLayout"
        Identifier     "seatX"
        Screen      X  "ScreenX" 0 0
        InputDevice    "MouseX" "CorePointer"
        InputDevice    "KeyboardX:1" "CoreKeyboard"
        InputDevice    "KeyboardX:2" "AlwaysCore"
EndSection
Warning: If not the AlwaysCore option is set for the second device you will get a LookupDeviceIntRec id=0x0 not found error each time a multimedia key is pressed.

For more information see: HOWTO_Microsoft_Natural_Ergonomic_Keyboard_4000

[edit] Testing

Now you want to test if it works, right?

  • Run X -layout alltogether to see if you got a working config. If not have a look at the standard output and at the /var/log/Xorg.0.log. May your intuition or The Internet help you solve your troubles.
  • Run X -layout seatX per seat and make sure you got the right input devices to the right monitor.

[edit] Integration with KDE / kdm

File: /usr/kde/3.5/share/config/kdm/kdmrc 
### General settings ###
# List of permanent displays. Displays with a hostname are foreign. A display
# class may be specified separated by an underscore.
# Default is ":0"
StaticServers=:0,:1 ### List as many as seats
# List of on-demand displays. See StaticServers for syntax.
# Default is ""
ReserveServers=:2,:3 ### Put the rest here as a reserve

### Per seat ###
[X-:0-Core]
ServerArgsLocal=-nolisten tcp -layout seat0 -sharevts -novtswitch -isolateDevice PCI:x:y:z

Also change the Keyboard model to Evdev-managed keboard in the Control Center:
Regional & Accessibility » Keyboard Layout » Keyboard model » Evdev-managed keyboard

Note: There is also a KDE bug#125559 that causes the Up Arrow to be confused with PrintScrn on evdev keyboards, which should be fixed in the next release (KDE 3.5.6)

[edit] Integration with GNOME / gdm

File: /etc/X11/gdm/custom.conf 
### Server settings ###
 [servers]
 0=Standard0
 1=Standard1
 ...
 
### per seat - these sections will need to be created ###
 [server-Standard0]
 name=Standard server
 command=/usr/X11R6/bin/X -novtswitch -sharevts -isolateDevice PCI:x:y:z -layout seat0
 flexible=false

[edit] Getting Meta keys to work again

evdev keyboard drivers are slightly problematic. Make sure you are using x11-misc/xkeyboard-config instead of x11-misc/xkbdata. If your windows keys don't work, add 'xmodmap -e "add Mod4 = Super_L Super_R" &' to your xsession, xinitrc, foobar.desktop, or whichever X startup script you use.

[edit] References

[edit] TODO

  • Might Option "IsolateDevice" "bus-id" work as well in the xorg.conf? I guess yes.

Have to try this next weekend...

  • Might Option "DontVTSwitch" "boolean" work as well in the xorg.conf? <yes>
  • Is there an Option for xorg.conf replacing the command line switch -sharevts ?
  • Is there an Option
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