[ale] Monitor won't display more than 640x480

[Mike Millson]

> How do I get X to ignore the laptop display and probe the external
> monitor for settings? Before I start X, I make sure just the external
> monitor is displaying, then start x. But when I do that, the laptop
> display comes on, so that tells me it's fixed on the internal display.
> 

I figured this out. You have to set some video card specific options. My
Dell Latitude C510 has an ATI Radeon Mobility M6 LY (chip 4c59), which
uses the radeon driver (see man radeon).

Basically what you do is clone the laptop display onto the external
monitor. Below is my XF86Config file.

The important lines are:

(1) Turn off the laptops monitor when you start X:
Option      "PanelOff"  "true"

(2) Set the HSync and VRefress for the external monitor:
Option      "CloneHSync"  "30-95"
Option      "CloneVRefresh"  "50-152"

(3) Tell the external monitor what resolution you want:
Option      "CloneMode"  "1024x768"


========================================================================

# XFree86 4 configuration created by redhat-config-xfree86

Section "ServerLayout"
	Identifier     "Default Layout"
	Screen      0  "Screen0" 0 0
	InputDevice    "Mouse0" "CorePointer"
	InputDevice    "Mouse1" "SendCoreEvents"
	InputDevice    "Keyboard0" "CoreKeyboard"
EndSection

Section "Files"

# RgbPath is the location of the RGB database.  Note, this is the name
of the 
# file minus the extension (like ".txt" or ".db").  There is normally
# no need to change the default.
# Multiple FontPath entries are allowed (they are concatenated together)
# By default, Red Hat 6.0 and later now use a font server independent of
# the X server to render fonts.
	RgbPath      "/usr/X11R6/lib/X11/rgb"
	FontPath     "unix/:7100"
EndSection

Section "Module"
	Load  "dbe"
	Load  "extmod"
	Load  "fbdevhw"
	Load  "glx"
	Load  "record"
	Load  "freetype"
	Load  "type1"
	Load  "dri"
EndSection

Section "InputDevice"

# Specify which keyboard LEDs can be user-controlled (eg, with xset(1))
#	Option	"Xleds"		"1 2 3"
# To disable the XKEYBOARD extension, uncomment XkbDisable.
#	Option	"XkbDisable"
# To customise the XKB settings to suit your keyboard, modify the
# lines below (which are the defaults).  For example, for a non-U.S.
# keyboard, you will probably want to use:
#	Option	"XkbModel"	"pc102"
# If you have a US Microsoft Natural keyboard, you can use:
#	Option	"XkbModel"	"microsoft"
#
# Then to change the language, change the Layout setting.
# For example, a german layout can be obtained with:
#	Option	"XkbLayout"	"de"
# or:
#	Option	"XkbLayout"	"de"
#	Option	"XkbVariant"	"nodeadkeys"
#
# If you'd like to switch the positions of your capslock and
# control keys, use:
#	Option	"XkbOptions"	"ctrl:swapcaps"
# Or if you just want both to be control, use:
#	Option	"XkbOptions"	"ctrl:nocaps"
#
	Identifier  "Keyboard0"
	Driver      "keyboard"
	Option	    "XkbRules" "xfree86"
	Option	    "XkbModel" "pc105"
	Option	    "XkbLayout" "us"
EndSection

Section "InputDevice"
	Identifier  "Mouse0"
	Driver      "mouse"
	Option	    "Protocol" "PS/2"
	Option	    "Device" "/dev/psaux"
	Option	    "ZAxisMapping" "4 5"
	Option	    "Emulate3Buttons" "yes"
EndSection

Section "InputDevice"
	Identifier  "Mouse1"
	Driver      "mouse"
	Option	    "Protocol" "Microsoft"
	Option	    "Device" "/dev/ttyS0"
	Option	    "ZAxisMapping" "4 5"
	Option	    "Emulate3Buttons" "no"
EndSection

Section "Monitor"
	Identifier   "LCD"
	VendorName   "Monitor Vendor"
	ModelName    "Dell 1024x768 Laptop Display Panel"
	HorizSync    31.5 - 48.52
	VertRefresh  59.0 - 75.0
	Option	    "dpms"
EndSection

Section "Device"
	Identifier  "VideoCard0"
	Driver      "radeon"
	VendorName  "Videocard vendor"
	BoardName   "ATI Radeon Mobility M6"
	BusID       "PCI:1:0:0"
	VideoRam    16384
	Option      "AGPMode"  "4"
	Option      "MonitorLayout" "LVDS, CRT" 
	Option      "PanelOff"  "true"
	Option      "CloneHSync"  "30-95"
	Option      "CloneVRefresh"  "50-152"
	Option      "CloneMode"  "1024x768"
	Option      "AGPFastWrite"  "true"
	Option      "OverlayOnCRTC2"  "true"
EndSection

Section "Screen"
	Identifier "Screen0"
	Device     "VideoCard0"
	Monitor    "LCD"
	DefaultDepth     24
	SubSection "Display"
		Depth     24
		Modes    "1024x768"
	EndSubSection
	SubSection "Display"
		Depth     8
		Modes    "1024x768"
	EndSubSection
	SubSection "Display"
		Depth     16
		Modes    "1024x768"
	EndSubSection
EndSection

Section "DRI"
	Group        0
	Mode         0666
EndSection