Dual Head configやり直し。

あまりにもよく落ちるので、見直した。体感的な描画速度も速くなった。安定したかどうかはしばらく様子を見る。

Section "ServerLayout"
    Identifier     "Multihead layout"
    Screen      0  "theScreen" 0 0
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
    Option         "Xinerama" "on"
    Option         "Clone" "off"
EndSection

Section "Files"
    FontPath        "unix/:7100"
EndSection

Section "Module"
          #Load  "dbe"
          #Load  "extmod"
          #Load  "type1"
          #Load  "freetype"
    Load           "glx"
EndSection

Section "InputDevice"

  # generated from default
    Identifier     "Mouse0"
    Driver         "mouse"
    Option         "Protocol" "auto"
    Option         "Emulate3Buttons" "no"
    Option         "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"

  # generated from data in "/etc/sysconfig/keyboard"
    Identifier     "Keyboard0"
    Driver         "kbd"
    Option         "XkbLayout" "us"
    Option         "XkbModel" "pc105"
EndSection

Section "Monitor"
    Identifier     "Monitor0"
    VendorName     "BenQ"
    ModelName      "G2220HD"
    DisplaySize     1920    1080
    Option         "DPMS"
EndSection

Section "Monitor"
    Identifier     "Monitor1"
    VendorName     "BenQ"
    ModelName      "G2220HD"
    DisplaySize     1920    1080
    Option         "DPMS"
EndSection