XGL with Xinerama [Screenshot]

Message

korean_sensation · Post by **korean_sensation** » Wed Mar 15, 2006 7:38 am

Having two flatscreens on dual NVIDIA GeForce 6600GT, I decided to see how nicely XGL worked with Xinerama. Too bad NVIDIA's SLI only works with one screen...

The only thing about this setup is that currently, I can't seem to get direct rendering enabled (currently shows "direct rendering: no" if I run glxinfo) and the entire GUI suffers from massive lag when I start doing CPU intensive tasks (such as emerging bunch of packages). Perhaps there's a bug in AMD64 version of NVIDIA glx drivers? If anyone know how to get direct rendering enabled for XGL on Xorg 7.0, let me know.

Other than that, it works like a charm. So those with two monitors wanting to try out XGL, don't be afraid to try it out!

Here are the screenshots:
http://www.andrewjo.com/images/rotate.png
Rotating "Cube" (more like rotating rectangle)

http://www.andrewjo.com/images/sort.png
Window sorting

http://www.andrewjo.com/images/switch.png
Alt+Tab switching

NOTE: Compiz window manager is not multi-monitor "aware". It will maximize the window across multiple monitors; very annoying if you maximize Firefox and have a separation in the middle of the Google search textbox. Hopefully this will get fixed sooner or later.

If you have comments or questions, feel free!

linuxkrn · Post by **linuxkrn** » Wed Mar 15, 2006 5:14 pm

The thing with direct rendering is supposed to be that way. What I recall from reading the XGL design is that things are passed off to mesa, which holds the real "direct rendering" for the Xorg server. Then apps request to opengl render and mesa accepts it and then passes that on to the card. So you are really getting direct rendering, just not giving it to one app. Is there a speed hit, yes, but you can run more then one opengl app and have the desktop GL accelerated at the same time.

Go read the XGL design stuff for more info on that.

I also agree that the compiz + xinerama thing is a major pain! Hoping they fix that soon.

korean_sensation · Post by **korean_sensation** » Wed Mar 15, 2006 7:17 pm

Thanks for clearing that up for me linuxkrn

Another thing is that any OpenGL screensavers are REALLY slow on Xinerama. Since the monitors are connected to two separate video cards, shouldn't each video card render 3D for each screen? Or does it not work that way? I have pretty decent video cards so it shouldn't slow down like that.

I get something like 1-2 FPS if I run my favorite Flurry screensaver.

linuxkrn · Post by **linuxkrn** » Wed Mar 15, 2006 8:04 pm

The problem is having two vidieo cards. Xinerama has to store the memory in RAM, and hence it is all drawn then pushed out to the cards memory. It is NOT designed for opengl acceleration. What you need is a dual head card then it works just as a fast as one head.

Or you can just setup two displays, :0.0 and :0.1. You can't move windows, but the mouse can move in between monitors and you get opengl acceleration on each one.

korean_sensation · Post by **korean_sensation** » Wed Mar 15, 2006 10:19 pm

I did try setting up two separate displays but it was pain getting XGL to run on both screens separately. Either way, I'll try using the dual head method when I get home after work. Secondary video card is used mostly for SLI purposes anyway so it doesn't really matter to me as long as it runs smoothly. Only if it were possible to run the video cards in SLI mode AND have dual display at the same time (not currently possible according to NVIDIA). Thanks for the help!

grad_guy · Post by **grad_guy** » Wed Mar 22, 2006 7:36 am

Well, I'd better jump in to show that ATI is behind.
Xgl and compiz are setup with latest ati-drivers(fglrx) and coffebuzz's overlay.
This is the result from Ati Radeon 9800Pro and P4 - 3.2Ghz-HT.

Dual head --dtop=horizontal ----> 2048x768
>>Stable & smooth, BUT resolution bigger than this gives "no screens found" error and the method with /etc/drirc doesn't help.

Dual head --dtop=clone -----> 1280x1024
>>Works nice, smooth and stable, it's just two same desktops that I see. Too bad.

Here is the xorg.conf I am using.
Here is how I start the desktop with gnome-light.

Code: Select all

#!/bin/bash
Xgl :1 -ac -accel glx:pbuffer -accel xv:pbuffer &
LD_LIBRARY_PATH=/usr/lib/opengl/xorg-x11/lib/ DISPLAY=:1 compiz gconf &
DISPLAY=:1 gnome-window-decorator &
DISPLAY=:1 /usr/libexec/gnome-settings-daemon &
DISPLAY=:1 nautilus -n --sync &
DISPLAY=:1 gnome-panel

I just use Ctrl+Alt+Backspace to kill Xgl.

If anyone can get Dual Head --dtop=horizontal with 2560x1024 on Ati, please let me know how to.
Thanks.

OneInchMen · Post by **OneInchMen** » Wed Mar 22, 2006 8:36 am

I have 2 monitors connected to my NVidia 6200 (or something) and it's not Compiz which isn't multiple monitor aware; it's the whole of Xgl.

Even the login screen (XDM) is centered on both screens instead of centered on my primary monitor. Switching back to Xorg (cd /usr/bin && ln -fs Xorg X) and ctrl-alt-backspacing puts the login dialog back to the correct behavior.

I test Xgl once in a while, but as long as there is no Xinerama/Twinview support and no decent window decorator available, I just have a quick peek and restore Xorg again...

korean_sensation · Post by **korean_sensation** » Wed Mar 22, 2006 5:20 pm

Good point on the XDM, except I do have to point out the window manager still has to be Xinerama aware. The Metacity window manager has a USE flag for Xinerama when you emerge it. XDM is a different story. Even if XGL WAS Xinerama aware, my speculation is that if Compiz isn't aware of the multi-monitor setting, dialog boxes will appear in the middle between two monitors and windows will maximize across two screens.

I haven't done this myself so don't take my word for it, but I'm guessing in Xorg, if you re-emerge Metacity with USE="-xinerama", Metacity will behave like Compiz and lose multi-monitor support.

OneInchMen · Post by **OneInchMen** » Thu Mar 23, 2006 9:13 am

I use XFWM4, that's XFCE's window manager. It has perfect Xinerama/TwinView support, but it looses all dual(+)monitor options when running it on XGL.

Compiz is also a window manager so it will replace XFWM4. To get decorations on my windows, I need to emerge the whole KDE or Gnome DE. This is not an option. There is an obvious reason why I run XFCE and everybody who has done so can agree with me... Try to build the latest svn versions of KDE every day for example...

I hope someone comes up with a simple window decorator plugin really soon...

m4chine · Post by **m4chine** » Thu Apr 20, 2006 3:41 pm

I've installed Xgl and compiz on a GeForce FX 5500 with dual ouptuts. I know that Xgl and compiz both currently do not support Xinerama, but I cant seem to get dual monitors working at all once in compiz. Running Xgl and fluxbox I at least get both monitors working, w/o xinerama.

When I boot up gdm starts, centering the login console on both monitors (Xgl byproduct), I login to fluxbox and I get no Xinerama (ok), but both monitors work. I logout to gdm console, I then login to Gnome/Compiz, by second monitor turns off until I restart xdm/gdm. Then I can boot back into fluxbox with both monitors.

korean_sensation: how were you able to get both monitors to work in compiz? I'm very anxious to get compiz running with dual monitors

Thanks for your help.

korean_sensation · Post by **korean_sensation** » Thu Apr 20, 2006 6:11 pm

Hi m4chine, unlike doing TwinView like you did, I have two identical video cards where each monitor is hooked up to. I followed the XGL HOWTO and then immediately followed Dual Monitor HOWTO. I got X to autodetect the video configuration:

Code: Select all

X -configure

I advise that you compare your xorg.conf with the one in the Dual Monitor HOWTO. Hope this helps. Good luck!

EDIT: This link may be more relevant for you: XGL Multihead HOWTO

m4chine · Post by **m4chine** » Thu Apr 20, 2006 7:15 pm

Thanks korean_sensation, this looks like exactly what I needed. I'm at work atm, but I'll post my hopefull success when I get home

xanas3712 · Post by **xanas3712** » Sat Apr 22, 2006 11:18 am

Oh cool, this may help me as well.. thanks a ton I was searching on google with no good results..

tomk · Post by **tomk** » Sat Apr 22, 2006 11:54 am

Moved from Desktop Environments to Unsupported Software.