debian etch / PowerMac G5でデュアルディスプレイ

ATI radeong 9800 ProのADC出力とDVI出力それぞれにディスプレイをつないた。xorgの設定が微妙に難しくてハマった。以下にxorg.confを全文転載しておく。

# /etc/X11/xorg.conf (xorg X Window System server configuration file)
#
# This file was generated by dexconf, the Debian X Configuration tool, using
# values from the debconf database.
#
# Edit this file with caution, and see the /etc/X11/xorg.conf manual page.
# (Type "man /etc/X11/xorg.conf" at the shell prompt.)
#
# This file is automatically updated on xserver-xorg package upgrades *only*
# if it has not been modified since the last upgrade of the xserver-xorg
# package.
#
# If you have edited this file but would like it to be automatically updated
# again, run the following command:
#   sudo dpkg-reconfigure -phigh xserver-xorg

Section "Files"
	FontPath	"/usr/share/fonts/X11/misc"
	FontPath	"/usr/X11R6/lib/X11/fonts/misc"
	FontPath	"/usr/share/fonts/X11/cyrillic"
	FontPath	"/usr/X11R6/lib/X11/fonts/cyrillic"
	FontPath	"/usr/share/fonts/X11/100dpi/:unscaled"
	FontPath	"/usr/X11R6/lib/X11/fonts/100dpi/:unscaled"
	FontPath	"/usr/share/fonts/X11/75dpi/:unscaled"
	FontPath	"/usr/X11R6/lib/X11/fonts/75dpi/:unscaled"
	FontPath	"/usr/share/fonts/X11/Type1"
	FontPath	"/usr/X11R6/lib/X11/fonts/Type1"
	FontPath	"/usr/share/fonts/X11/100dpi"
	FontPath	"/usr/X11R6/lib/X11/fonts/100dpi"
	FontPath	"/usr/share/fonts/X11/75dpi"
	FontPath	"/usr/X11R6/lib/X11/fonts/75dpi"
	# path to defoma fonts
	FontPath	"/var/lib/defoma/x-ttcidfont-conf.d/dirs/TrueType"
EndSection

Section "Module"
	Load	"i2c"
	Load	"bitmap"
	Load	"ddc"
	Load	"dri"
	Load	"extmod"
	Load	"freetype"
	Load	"glx"
	Load	"int10"
	Load	"type1"
	Load	"vbe"
EndSection

Section "InputDevice"
	Identifier	"Generic Keyboard"
	Driver		"kbd"
	Option		"CoreKeyboard"
	Option		"XkbRules"	"xorg"
	Option		"XkbModel"	"pc104"
	Option		"XkbLayout"	"us"
EndSection

Section "InputDevice"
	Identifier	"Configured Mouse"
	Driver		"mouse"
	Option		"CorePointer"
	Option		"Device"		"/dev/input/mice"
	Option		"Protocol"		"ExplorerPS/2"
	Option		"Emulate3Buttons"	"true"
EndSection

Section "Device"
	Identifier	"Videocard0"
	Driver		"ati"
#	Option		"UseFBDev"		"true"
	Option		"VideoOverlay"		"on"
	Option		"CRT2Position"		"RightOf"
	Option		"CRT2HSync"		"28-64"
	Option		"CRT2VRefresh"		"43-60"
#	Option		"MetaModes"		"1600x1200-1280x1024"
#	Option		"MetaModes"		"1280x1024-1024x768"
	Option		"MetaModes"		"1280x1024-1280x1024"
	Option		"MergedFB"		"true"
	Screen		0
EndSection

Section "Monitor"
	Identifier	"Monitor0"
	Option		"DPMS"
	HorizSync	28-64
	VertRefresh	43-60
	Option		"dpms"
EndSection

Section "Screen"
	Identifier	"Screen0"
	Device		"Videocard0"
	Monitor		"Monitor0"
	DefaultDepth	24
	SubSection "Display"
		Depth		1
		Modes		"1280x1024" "1024x768" "800x600" "640x480"
	EndSubSection
	SubSection "Display"
		Depth		4
		Modes		"1280x1024" "1024x768" "800x600" "640x480"
	EndSubSection
	SubSection "Display"
		Depth		8
		Modes		"1280x1024" "1024x768" "800x600" "640x480"
	EndSubSection
	SubSection "Display"
		Depth		15
		Modes		"1280x1024" "1024x768" "800x600" "640x480"
	EndSubSection
	SubSection "Display"
		Depth		16
		Modes		"1280x1024" "1024x768" "800x600" "640x480"
	EndSubSection
	SubSection "Display"
		Depth		24
		Modes		"1280x1024" "1024x768" "800x600" "640x480"
	EndSubSection
EndSection

Section "ServerLayout"
	Identifier	"Multihead"
	Screen	0	"Screen0"	0 0
	InputDevice	"Generic Keyboard"
	InputDevice	"Configured Mouse"
	Option		"Xinerama"	"off"
	Option		"Clone"		"off"
EndSection