voici mon xorg.conf, peut etre que le probleme vient de la :
Section "ServerLayout"
Identifier "Default Layout"
Screen 0 “aticonfig-Screen[0]” 0 0
InputDevice "Generic Keyboard"
InputDevice "Configured Mouse"
InputDevice "Synaptics Touchpad"
EndSection
Section “Files”
# local font server
# if the local font server has problems, we can fall back on these
FontPath "unix/:7100"
FontPath "/usr/share/fonts/X11/misc"
FontPath "/usr/lib/X11/fonts/misc"
FontPath "/usr/share/fonts/X11/cyrillic"
FontPath "/usr/lib/X11/fonts/cyrillic"
FontPath "/usr/lib/X11/fonts/100dpi/:unscaled"
FontPath "/usr/lib/X11/fonts/75dpi/:unscaled"
FontPath "/usr/share/fonts/X11/Type1"
FontPath "/usr/lib/X11/fonts/Type1"
FontPath "/usr/share/fonts/X11/CID"
FontPath "/usr/lib/X11/fonts/CID"
FontPath "/usr/share/fonts/X11/100dpi"
FontPath "/usr/lib/X11/fonts/100dpi"
FontPath "/usr/share/fonts/X11/75dpi"
FontPath "/usr/lib/X11/fonts/75dpi"
EndSection
Section "Module"
Load "bitmap"
Load "dbe"
Load "ddc"
Load "dri"
Load "extmod"
Load "freetype"
Load "glx"
Load "int10"
Load "record"
Load "v4l"
Load "vbe"
EndSection
Section "InputDevice"
Identifier "Generic Keyboard"
Driver "keyboard"
Option "CoreKeyboard"
Option “XkbRules” "xorg"
Option “XkbModel” "pc105"
Option “XkbLayout” "fr"
EndSection
Section "InputDevice"
Identifier "Configured Mouse"
Driver "mouse"
Option "CorePointer"
Option “Device” "/dev/input/mice"
Option “Protocol” "ImPS/2"
Option “Emulate3Buttons” "true"
Option “ZAxisMapping” "4 5"
EndSection
Section "InputDevice"
Identifier "Synaptics Touchpad"
Driver "synaptics"
Option “SendCoreEvents” "true"
Option “Device” "/dev/psaux"
Option “Protocol” "auto-dev"
Option “HorizScrollDelta” "0"
EndSection
Section "Monitor"
Identifier "�ran g��ique"
HorizSync 30.0 - 60.0
VertRefresh 50.0 - 75.0
ModeLine “1280x800@60” 83.9 1280 1312 1624 1656 800 816 824 841
Option "DPMS"
EndSection
Section "Monitor"
Identifier "aticonfig-Monitor[0]"
Option “VendorName” "ATI Proprietary Driver"
Option “ModelName” "Generic Autodetecting Monitor"
Option “DPMS” "true"
EndSection
Section "Device"
Identifier “ATI Technologies, Inc. RV350 [Mobility Radeon 9600 M10]”
Driver “ati”
Driver "radeon"
Option "VideoOverlay" "on"
Option "XAANoOffscreenPixmaps" "true"
Option "AddARGBGLXVisuals" "On"
BusID "PCI:1:0:0"
EndSection
Section "Device"
Identifier "aticonfig-Device[0]"
Driver "fglrx"
EndSection
Section "Screen"
Identifier "Default Screen"
Device "ATI Technologies, Inc. RV350 [Mobility Radeon 9600 M10]"
Monitor "�ran g��ique"
DefaultDepth 24
Option “RenderAccel” "true"
SubSection "Display"
Depth 1
Modes “1280x960” “1280x854” “1280x800” “1280x768” “1200x800” “1152x864” “1152x768” “1024x768” “800x600” "640x480"
EndSubSection
SubSection "Display"
Depth 4
Modes “1280x960” “1280x854” “1280x800” “1280x768” “1200x800” “1152x864” “1152x768” “1024x768” “800x600” "640x480"
EndSubSection
SubSection "Display"
Depth 8
Modes “1280x960” “1280x854” “1280x800” “1280x768” “1200x800” “1152x864” “1152x768” “1024x768” “800x600” "640x480"
EndSubSection
SubSection "Display"
Depth 15
Modes “1280x960” “1280x854” “1280x800” “1280x768” “1200x800” “1152x864” “1152x768” “1024x768” “800x600” "640x480"
EndSubSection
SubSection "Display"
Depth 16
Modes “1280x960” “1280x854” “1280x800” “1280x768” “1200x800” “1152x864” “1152x768” “1024x768” “800x600” "640x480"
EndSubSection
SubSection "Display"
Depth 24
Modes “1280x960” “1280x854” “1280x800” “1280x768” “1200x800” “1152x864” “1152x768” “1024x768” “800x600” "640x480"
EndSubSection
EndSection
Section "Screen"
Identifier "aticonfig-Screen[0]"
Device "aticonfig-Device[0]"
Monitor "aticonfig-Monitor[0]"
DefaultDepth 24
SubSection "Display"
Viewport 0 0
Depth 24
EndSubSection
EndSection
Section "DRI"
Mode 0666
EndSection
Section "Extensions"
Option “Composite” "Enable"
EndSection