I have just installed the Linux ATI 3D graphics diver onto my Inspiron 8600 laptop.
A good site on how to download and compile the fglrx module/driver can be found here.
Once you have followed the instructions above, you will need to make sure that your /etc/X11/XF86Config-4 file is configured properly.
Here are some relevant sections of a working XF86Config on my INSPIRON 8600 ATI RADEON PR0 9600/DISPLAY 15.5" 16/10 Ratio. Of particular interest would be the Modline configurations for people with a similar setup
Section "Device"
Identifier "Generic Video Card"
#Identifier "ATI Graphics Adapter"
Driver "fglrx"
# ### generic DRI settings ###
# === disable PnP Monitor ===
#Option "NoDDC"
# === disable/enable XAA/DRI ===
Option "no_accel" "no"
Option "no_dri" "no"
# === misc DRI settings ===
Option "mtrr" "off" # disable DRI mtrr mapper, driver has its own code for mtrr
# ### FireGL DDX driver module specific settings ###
# === Screen Management ===
Option "DesktopSetup" "0x00000100"
Option "MonitorLayout" "AUTO, NONE"
Option "IgnoreEDID" "off"
Option "HSync2" "unspecified"
Option "VRefresh2" "unspecified"
Option "ScreenOverlap" "0"
# === TV-out Management ===
Option "NoTV" "no"
Option "TVStandard" "PAL-B"
Option "TVHSizeAdj" "0"
Option "TVVSizeAdj" "0"
Option "TVHPosAdj" "0"
Option "TVVPosAdj" "0"
Option "TVHStartAdj" "0"
Option "TVColorAdj" "0"
Option "GammaCorrectionI" "0x00000000"
Option "GammaCorrectionII" "0x00000000"
# === OpenGL specific profiles/settings ===
Option "Capabilities" "0x00008000"
# === Video Overlay for the Xv extension ===
Option "VideoOverlay" "on"
# === OpenGL Overlay ===
# Note: When OpenGL Overlay is enabled, Video Overlay
# will be disabled automatically
Option "OpenGLOverlay" "on"
# === Center Mode (Laptops only) ===
Option "CenterMode" "off"
# === Pseudo Color Visuals (8-bit visuals) ===
Option "PseudoColorVisuals" "off"
# === QBS Management ===
Option "Stereo" "off"
Option "StereoSyncEnable" "1"
# === FSAA Management ===
Option "FSAAEnable" "no"
Option "FSAAScale" "1"
Option "FSAADisableGamma" "no"
Option "FSAACustomizeMSPos" "no"
Option "FSAAMSPosX0" "0.000000"
Option "FSAAMSPosY0" "0.000000"
Option "FSAAMSPosX1" "0.000000"
Option "FSAAMSPosY1" "0.000000"
Option "FSAAMSPosX2" "0.000000"
Option "FSAAMSPosY2" "0.000000"
Option "FSAAMSPosX3" "0.000000"
Option "FSAAMSPosY3" "0.000000"
Option "FSAAMSPosX4" "0.000000"
Option "FSAAMSPosY4" "0.000000"
Option "FSAAMSPosX5" "0.000000"
Option "FSAAMSPosY5" "0.000000"
# === Misc Options ===
Option "UseFastTLS" "0"
Option "BlockSignalsOnLock" "on"
Option "UseInternalAGPGART" "yes"
Option "ForceGenericCPU" "no"
BusID "PCI:1:0:0" # vendor=1002, device=4e50
Screen 0
#Screen "Default Screen"
EndSection
Section "Monitor"
Identifier "Generic Monitor"
HorizSync 31.5-110.0
VertRefresh 30.0-90.0
DisplaySize 330 210
Modeline "1920x1200" 161.750000 1920 2020 2052 2184 1200 1202 1208 1235 +hsync +vsync
Option "DPMS"
EndSection
Section "Screen"
Identifier "Screen 0"
Device "Generic Video Card"
Monitor "Generic Monitor"
DefaultDepth 24
SubSection "Display"
Depth 24
Virtual 1920 1200
EndSubSection
EndSection