Enable Multiseat support in MeeGo

This is a step-by-step guide to enable Multiseat[1] on single video card with Xfce[2] desktop environment, based on Xephyr[3] and XRandR[4].

Contents 1 Note 2 Setup 3 Performance 4 Limitation

Note

• 1) Xfce desktop environment is enabled, Mutter based desktop environment doesn't work per testing.
• 2) A lot of integration work needs to be done with uxlaunch/ConsoleKit/etc.
• 3) All below commands are assumed to run with "root", you'd better "ssh" to the netbook to copy/paste some of those commands.

Setup

• 1) Install MeeGo 1.2.0 for Netbook, image is here [5].

• 2) Edit /etc/inittab, change default runlevel from 5 to 3, then reboot

• 3) Setup Proxy

       export http_proxy=http://<proxy_server>:<proxy_port>
       export no_proxy=.intel.com,10.0.0.0/8

• 4) Setup Repo

       wget http://download.meego.com/live/MeeGo:/1.2.0:/oss:/Update:/Testing/MeeGo_1.2.0/MeeGo:1.2.0:oss:Update:Testing.repo
       wget http://download.meego.com/live/home:/yyin2:/branches:/MeeGo:/1.2.0:/oss:/Update:/Testing/MeeGo_1.2.0/home:yyin2:branches:MeeGo:1.2.0:oss:Update:Testing.repo
       wget http://download.meego.com/live/home:/yyin2:/branches:/MeeGo:/1.2.0:/oss/standard/home:yyin2:branches:MeeGo:1.2.0:oss.repo
       zypper refresh

• 5) Install modified xorg-xephyr, xfce4-panel, mdm from "yyin2" repo

       zypper install xorg-x11-server-Xephyr xfce-panel mdm

• 6) Setup kebyoard/mouse

       mkdir -p /etc/mdm/devices
       cd /etc/mdm/devices
       ln -sf /dev/input/by-id/xxxx keyboard1
       ln -sf /dev/input/by-id/xxxx keyboard2
       ln -sf /dev/input/by-id/xxxx mouse1
       ln -sf /dev/input/by-id/xxxx mouse2

• 7) Setup X

       xrandr -q  # there should be at least two monitors listed out, e.g. "LVDS1", "VGA1", or else STOP here.
       Xorg -configure
       cp /root/xorg.conf.new /etc/mdm/xorg.conf.mdm
       <add lines "Virtual 2048 2048" to /etc/mdm/xorg.conf.mdm Display section, this is the key "magic" of this guide, a big Virtual Screen will be assembled by LVDS1+VGA1, the width (or the height) should be bigger than the sum of width (or height) of LVDS1+VGA1>
       nohup /usr/bin/X -config /etc/mdm/xorg.conf.mdm vt08 -logfile /etc/mdm/xorg.mdm.log -dpms -s 0 :0 >/dev/null 2>/dev/null &

• 8) Run Xephyr

       xrandr --output LVDS1 --mode 1024x600
       xrandr --output VGA1 --mode 1024x768  
       xrandr --output VGA1 --right-of LVDS1

       export DISPLAY=:0
       seat-parent-window 1024x600+0+0 seat-parent-window0-LVDS1 & 
       seat-parent-window 1024x768+1024+0 seat-parent-window0-VGA1 &

       xwininfo -name seat-parent-window0-LVDS1 (get the window id, e.g. 0x200001)
       xwininfo -name seat-parent-window0-VGA1  (get the window id, e.g. 0x400001)

       export DISPLAY=:0; Xephyr :1  -dpms -s 0 -br :1 -parent 0x200001 -mouse evdev,,device=/etc/mdm/devices/mouse1 -keybd evdev,,device=/etc/mdm/devices/keyboard1,xkbmodel=evdev,xkblayout=us -nolisten tcp vt9 &	
       export DISPLAY=:1; xterm &  #test the keyboard/mouse of 1st seat in the terminal

       export DISPLAY=:0; Xephyr :2  -dpms -s 0 -br :2 -parent 0x400001 -mouse evdev,,device=/etc/mdm/devices/mouse2 -keybd evdev,,device=/etc/mdm/devices/keyboard2,xkbmodel=evdev,xkblayout=us -nolisten tcp vt9 &	
       export DISPLAY=:2; xterm &  #test the keyboard/mouse of 2nd seat in the terminal

• 9) Run xfwm4, xfce4-panel, xfce4-session

       zypper install xfce4-settings xfce4-taskmanager xfce4-mixer xfce4-battery-plugin  xfce-utils  xfce4-appfinder  Thunar thunar-vfs thunar-volman  
       export DISPLAY=:1; xfwm4; xfce4-session
       export DISPLAY=:2; xfwm4; xfce4-session

• 10) Now you should have two seats setup, each one has its own keyboard/mouse/monitor, and you can play different videos in two seats concurrently.

Performance

• Xehpyr for MeeGo has been enhanced for GL acceleration ([6]), you can simply compare the 3D performance by run the "glxgears" in native X, one Xephyr instance, two Xephyr instances. In my testing, the data are 70 FPS, 70 FPS, 50(x2) FPS respectively, no dramatic performance drop.
• Xvideo extension works in both Xephyr instances, in my testing to playing 2x480p ogv video (no hardware decoding) in two seats concurrently, it will cost about 85% CPU utilization with Acer Aspire One (Pinetrail based netbook).

Limitation

• The audio output are now mixed when playing two videos/audio streams concurrently, if you have another bluetooth headset, you can run "pacmd" and move one audio stream to the bluetooth sink, so that two audio streams are separated.
• The Chromium browser will always open a new "Tab" in the 1st seat if you launch it in the 2nd seat, probably some setting in Chromium says "Always start a new Tab instead of a new Window".