linux & ati dual head... suggestions?

I’m trying to run blender (Orange CVS) on linux (Fedora 4), and I ran into a bit of a snag. It seems that when the application tries to run on both screens, (Which it does by default), the second monitor won’t show it properly, due to a lack of hardware support. After a fair bit of googling, (and some friendly hints from these forums, ( )
I’ve come to the conclusion that the only way to get it working properly is to use MergedFB ( I just can’t figure out how to make it work!

I have a radeon 9800, using custom ATI drivers. (It says that the DRI drivers don’t support ATI’s 350 chipset). Does anybody have any ideas how to install / configure MergedFB, or where I could get some information?

Sorry if this is a stupid question, as far as linux goes, I’m still very much a newbie.

I don’t belive ati drivers in linux support hardware acceleration on both displays [same with nvidia], I’m surprized you get hardware acceleration at all with a single x server spanned across two displays

I do that with my nvidia card all the time.

I think the proprietary ATI drivers allow it, too. However, it’s been forever since I’ve had a machine with an ATI card in it, so my information may be a bit dated.

Check out ATI drivers for Linux from


hi, i use linux and have Blender over two 21" monitors with a cheap basic 128mb Nvidia FX5200 and nvidia’s proprietary drivers. It works flawlessly without having to get into the realms of obscure work arounds. Their like $25 or something. Would an alternative solution be to just buy such a vid card and save the hassle with ati?

good luck

TwinView (no xinerama) and a window manager (xfce is the best I’ve tried, gnome and fluxbox have problems) that supports xinerama hints works best, but it can be done.

Ditto head is close… the answer is xinerama. You have to edit your xorg.conf file by hand to make it work, but it’s been a while scince I’ve done it… sorry Nvidia over here to…

You can use MergedFB for a hardware-accelerated dual-monitor setup.

Add these options to your xorg.conf file:

Section “Device”

Option “MergedFB” “On”
Option “CRT2HSync” “<2nd monitor’s hsync value>”
Option “CRT2VRefresh” “<2nd monitor’s vrefresh value>”
Option “CRT2Position” “RightOf” #this can vary according to your preferences

Section “Screen”

Virtual “2048x768” #or however big your combined desktop size is

All the info for MergedFB can be found on the radeon man page (# man radeon) or on this page (which is an HTML radeon man page):

MergedFB only works with the DRI Radeon driver. Don’t try this with fglrx.

EDIT: oh yeah, i almost forgot to mention: i’ve tried to use blender with a mergedfb setup before, and the blender window on the second monitor is always all black. maybe you will have better luck?