ATI Radeon 9600 with Compiz and Dual-Head

October 5th, 2007 · 4 Comments

This concerns configuring an ATI Radeon 9600 under Linux to be dual head and run compiz-fusion. I’m not going into detail on what options make compiz run faster, just how to get two screens working well with compiz.

I’m posting this because I had a hell of a time finding all the info on it.

Update: This is the significant portion of my xorg.conf.

Resources:
Radeon driver xorg settings
XGL Troubleshooting
Compiz wiki ATI notes

My desired setup: two CRTs side by side, each running at 1280×1024, giving me an effective desktop of 2560×1024.

For desktop effects to work, I had to run the ‘radeon’ driver, not the ‘ati’ nor ‘fglrx’ drivers. If one uses fglrx, I guess one can get by running XGL instead of AIGLX, but that locked up my X.

First important note: If fglrx was ever installed and you want to use ati or radeon, you need to fully remove fglrx (sudo apt-get remove –purge fglrx).

Second important note: To get a desktop spanning across two monitors, you want to use the MergedFB option in your xorg.conf. This provides Xinerama-like functionality. There are several options with that mode to provide different resolutions on each monitor with spanning.

Third important note: There is an apparent hardware limitation for these cards on texture sizes. The max texture size for 3D applications (including compiz) of 2048×2048). This means that if you have a desktop wider than 2048, you’ll either

have effects for half or 2/3 of the desktop/screen with white on the far right, or
a fully white screen with odd tearing on effects

There’s not much way around this at this point. Some people can fix it messing with ‘driconf’.
My solution at this point is to have one screen ‘Above’ instead of ‘RightOf’ in my xorg.conf (the two heights combine to 2048, so they fit into memory).

Anyway, that’s about it. ~~I’ll add my xorg.conf to this post, later. I can’t cause I’m on the laptop right now.~~

# xorg.conf significant sections for dual head + compiz on radeon 9600 XT # second screen on top of second screen, vertical orientation.


Section "Module"

	Load	"bitmap"

	Load	"ddc"

	Load	"dri"

	Load	"dbe"

	Load	"extmod"

	Load	"freetype"

	Load	"glx"

	Load	"int10"

	Load	"type1"

	Load	"vbe"

EndSection
Section "Device"

	Identifier	"Radeon"

	Driver "radeon"

	BusID  "PCI:1:0:0"

	Option "No2048Limit"

	Option "MergedFB" "true"

	Option "MergedXineramaCRT2IsScreen0" "true"

	Option "CRT2Position" "Above"

        Option "MetaModes" "1280x1024-1280x1024 1024x768-1024x768"
        Option  "DDCMode" "true"

	Option  "OpenGLOverlay" "Off"

	Option  "VideoOverlay" "on"

	Option  "GLOverlay" "false"

	Option  "OverlayOnCRTC1" "on"

        Option  "OverlayOnCRTC2" "on"

	Option  "MergedDPI" "75 75"

	Option  "AGPMode" "8"

	Option  "DRI" "true"

	Option  "ColorTiling" "on"

	Option  "EnablePageFlip" "true"

#DO NOT USE WITH RADEON 9600 Option "AccelMethod" "EXA"

	Option  "XAANoOffscreenPixmaps"

	Option  "RenderAccel" "true"

EndSection
Section "Monitor"

	Identifier	"Dell P991 [0]"

	Option		"DPMS"

	HorizSync       30-107

	VertRefresh     48-85

EndSection
Section "Screen"

	Identifier	"Screen0"

	Device		"Radeon"

	Monitor		"Dell P991 [0]"

	DefaultDepth	24

	SubSection "Display"

		Virtual 1280 2048

		Depth		24

		Modes	"1280x1024" "1024x768"

	EndSubSection

EndSection
Section "ServerLayout"

	Identifier	"Default Layout"

	Screen		"Screen0"

	InputDevice	"Generic Keyboard"

	InputDevice	"Configured Mouse"

	InputDevice     "stylus" "SendCoreEvents"

	InputDevice     "cursor" "SendCoreEvents"

	InputDevice     "eraser" "SendCoreEvents"

	Option          "AIGLX"         "true"

EndSection
Section "DRI"

	Mode	0666

EndSection

Section "Extensions" Option "Composite" "On" EndSection

Tags: code, linux, video

4 responses so far ↓

1 abracadabra // Oct 18, 2007 at 9:28 pm

Great job! I’m having a hard time trying to get Compiz at work on openSUSE 10.3, with a video card similar to yours.

I’d like to see your xorg.conf! Meanwhile, I’ll work with the valuable informations you’re giving.
Thanks.
2 criss // May 5, 2008 at 12:25 pm

What did you managed to do with it. I’m in the same situation. Weird enough is that in my xorg.conf the used driver is “radeon” and running fglrxinfo will say I use fglrx…
I’m not going to remove fglrx just yet..

Btw, how’s the overall performance after turning to radeon/compiz?
3 brink // Jun 3, 2008 at 8:01 am

Did you completely purge fglrx from your system? I had issues with mine in that it loaded the old fglrx module instead of the radeon one, for some reason.

Performance is alright… passable. I’m a little underwhelmed by the card — seems to peg CPU resources excessively. Lately I’ve gone back to fglrx and plain-jane desktop because I found that I had a choice of decent performance in WoW but only if I disabled desktop effects, or crap performance in WoW and desktop effects.
4 Oleg // Jul 29, 2008 at 4:09 pm

I saw this line in Xorg log, after setting AGPMode to 8:
(EE) RADEON(0): Illegal AGP Mode: 8 (valid values: 1, 2, 4), leaving at 4x

ATI Radeon 9600, ArchLinux 2008.6

fleshyorgans

tryin’ not to be a linux fanboy

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