Debian はログアウト後も lxde でスクリプトを実行し続けます。

Steamでいくつかのゲームをプレイしようとしています（特にハーフライフ2）が、デュアルモニター設定でXineramaを有効にすると悪名高い結果が発生します。

Could not find required OpenGL entry point 'glGetError'! Either your video card is unsupported, or your OpenGL driver needs to be updated.

私はで解決策を見つけましたアーチLinuxフォーラムしかし、LXDEを使用してシェルスクリプトとして実装することはできません。

#!/usr/sh
pkill -SIGTERM -f xsession
startx -- -layout Steam

正常にログアウトしましたが、pkillコンソールプロンプトに戻ってstartx実行されません。私がここで何を見逃しているのでしょうか？

user@home:~$ cat /etc/X11/xorg.conf.d/91-serverlayout-steam.conf
# nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings:  version 340.46  (pbuilder@zam904)  Fri Oct 17 21:29:34 UTC 2014

Section "ServerLayout"
    Identifier     "Steam"
    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      "Ancor Communications Inc VS248"
    HorizSync       30.0 - 83.0
    VertRefresh     50.0 - 76.0
    Option         "DPMS"
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    BoardName      "GeForce GTX 460 v2"
    BusID          "PCI:6:0:0"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    Option         "Stereo" "0"
    Option         "nvidiaXineramaInfoOrder" "DFP-0"
    Option         "metamodes" "nvidia-auto-select +0+0"
    Option         "SLI" "Off"
    Option         "MultiGPU" "Off"
    Option         "BaseMosaic" "off"
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection