LinuxQuestions.org - Multi-head with 3d acceleration?

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Multi-head with 3d acceleration?

Is there a way to enable 3d acceleration and multihead at the same time? What I'd like to be able to do is run Cedega on one CRT and have x-Chat/FireFox/Kopete up on the other CRT so I can play games and chat at the same time. From what I've seen Sax2 won't let me configure X to run that way, it's either 3d acceleration or multi-head, not both.

I'd prefer to not have to hand hack the x11 config files, but if that's what's needed I suppose I can figure something out :)

My system is an x86-64 based shuttle running SuSE 9.3 and a GeForce 5900XT card.

TwinView with nVidia suports 3D acceleration for both screens in dual head.

MergedFB also allows dual head with 3D acceleration. In this you get one big desktop :)

I think the basic X-dual-head should work. But if you use a pci video card, dri support will be much muted for that card no matter what.

You (currently) need a shared frame buffer between the two screens in order to get 3D acceleration with X. This can be done with Nvidia's TwinView technology, or if you want to drive yourself absolutely crazy with ATI's worthless technical support and hours on end tweaking your xorg.conf file when it doesn't work as documented, ATI's dual-port video cards with the proprietary ATI driver.

For ATI cards - you can use MergedFB and Xinerama in the 8500 sereis or higher, or ATI Big Desktop otherwise.

I agree that nVidia's multi-head is better.

I think the GeForce card used is neither. Xinerama will give one large desktop, but graphics acceleration for only the first screen. Someone correct me?

Quote:

Originally posted by Simon Bridge
ATI Big Desktop otherwise.

ATI Big Desktop has been identified as a cause of migraine headaches and rampages leading to mass executions. Heck, that's true of ATI drivers in general. Great hardware, abysmal software, and even more pathetic support. :D

Fairy-nuff... never actually seen it.

I found a program that says it can do it just as easy as in Windows its called YanC42, heres the link: http://www.ygriega.de/index.php?id=2&detail=1

Im downloading it right now to try it out.

Quote:

Originally Posted by KimVette

yeah..
i'm trying to configure a big-desktop on my ATI mobility radeon 9700, with monitor with different resolution, but this is driving me crazy!
Sigh, it's so easy with windows :)

The external monitor is running at 1280x1024, but the usable part is 1024x768 (as my laptop monitor) All other area of my external monitor are scrumbled..

It's even easier on Linux, if you have an nvidia card. Just upgraded three machines from ATI to Nvidia a few weeks ago here. It was a breeze!

Didn't upgrade my machine though - still on ATI, until I go Athlon X2. :)

evaimitico: the consensus is to not use big desktop. Better - not to use ATI cards. Of course: if this is a laptop, you may have no choice.

Especially from recent news: havn't ati stopped open-sourcing their old cards? (Something to do with an x-box contract?)

nvidia are not exactly free-software freindly, but they do seem to be determined to exploit their early lead in linux compatability. I'll be changing my nasty SiS board for nv 6600 very soon :)

Quote:

Originally Posted by Simon Bridge

evaimitico: the consensus is to not use big desktop. Better - not to use ATI cards. Of course: if this is a laptop, you may have no choice.

i have a laptop.... this is my fault :)

if i shouldn't use big desktop from ati, what is the best solution to have my two monitor at different resolution, and to be able to drag windows from a monitor to the other?

thanks a lot for any advice!

This is, of course, the problem.

ATI BigDesktop sits on top of Xinerama - but you lose 3D accel just using xinerama by itself. There is also MergedFB and Pseudo Xinerama.

As usual, the gentoo wiki has a nice presentation on the issues.
http://gentoo-wiki.com/HOWTO_Dual_Monitors

Quote:

As of the 8.19.10 ati-drivers release, Xinerama is natively supported inside the official ati-drivers themselves. Here are some tips for getting ATI "Big Desktop", the ATI Xinerama extension, and hardware DRI all working together. This configuration allows auto-detection of the presence of the secondary display.

Newer ati-drivers come with a handy aticonfig script that actually produces a working dual-head setup. This is the quick-and-easy way. Log out of X, backup your xorg.conf and run something akin to the following line:

Code:

# aticonfig --initial=dual-head --dtop=horizontal --screen-layout=right --iagp=off -v

# /etc/init.d/xdm restart

On one setup (amd64), KDE would instantly work with a streched desktop, when the monitors were the same size. On another setup (x86), KDE would only use one screen, when the monitors were of different size. Both systems did NOT use the xinerama flag. On this second system, all other tried window managers (Gnome and Fluxbox) would operate with no problems on both screens. In one occasion with a setup using gnome and monitors of different size, the bigger monitor was not completely filled.

If the aticonfig method does not work, you need to tweak xorg.conf a bit.

* Make sure your apps are compiled with Xinerama support - ( equery hasuse xinerama )
* Use fglrxconfig to generate a Big Desktop xorg.conf (Note - fglrxconfig is no longer available)
* Make sure Xinerama is NOT loaded as a module in xorg.conf. The Ati-drivers will take care of this automatically.

* Inside the ATI Device section of xorg.conf, check these settings
* Option "MonitorLayout" "LVDS,AUTO" - This is for my laptop, sets the first display to be in the internal LCD (LVDS), and to auto-detect the second display.
* Option "HSync2" "65" - This sets the horizontal sync for the secondary display.
* Option "VRefresh2" "60" - This sets the refresh rate of the secondary display.
* Option "Mode2" "1280x1024" - This sets the resolution of the secondary display, by default it'll try to use the identical resolutions on both displays.
* Option "EnablePrivateBackZ" "yes" - I couldn't get DRI and Big Desktop to work together until I set this....
* Option "UseInternalAGPGART" "no" - I use the kernel AGP modules, so I disable the ATI AGP support, YMMV.

Added by James Masson

... however, MergedFB is open source and can provide you with the big-desktop effect with 3D on both screens. I don't know about differing resolutions though.