(K)Ubuntu, 2 Displays, 2 Cards - Problem

Long story short, mainboard swap, AHCI activated.

Usually I am a Debian follower, the freeze of Squeeze however seems to have a bug and the installer refuses to install grub in the MBR with AHCI. As I am too old by now to have time to hack this and work around I thought I give Kubuntu a go again.

All nice’n’smooth.
However, what worked in Debian seeems an impossible task in Kubuntu - setting up X to span over both screens.

Installing the proprietary nvidia driver was a walk in the park. Was also easy to setup twinview to have both screens activated (I got one screen per graphics card)

However as soon as I try to activate xinerama to fool X into believing the twinview is one big screen to span the desktop over both, X starts up, nvidia logo flickers and I crash back to tty0.
With xinerama disabled it starts up just nice.

Granted an Ubuntu forum would be a better place to ask, but I think dualscreen/dualcard isn´t exactly a topic for the 101 ubuntu user and the issue has cropped up before for one of you guys.

It shouldn´t really make a difference that I am running Kubuntu instead of Ubuntu, KDE/Gnome just span over whatever X reports back to them.

Any hints, gentle pushes into a direction or linkage thats beyond ubuntu-noob forum is greatly appreciated.

What´s working in MacOS and Windows for ages out of the box still seems to be a stepchild in Linux.

Further research showed it seem to be some kind of problem with plasma. It almost seems as if xinerama is broken in KDE4 again(!) and will get some love with the next minor release.

As the install is still fresh, I´ll wipe kubuntu and try ubuntu to see if its a WM related problem or not. I´ll report back =)

Sidenote, If any of you encounter troubles with AHCI and crashing to busybox, start your kernel with “rootdelay=30” this way AHCI has time to intialize and report back to the kernel properly before just throwing a timeout.

this is essential to me, as I have my finger on the trigger to order a new Ubuntu 64 box. quick question: which ubuntu and video card / driver are you using?

KUbuntu 10.04 amd64
Ubuntu 10.04 amd64

Current driver - can´t tell, for the first time ever I didn´t compile my nvidia driver, but used the fancy hardware driver update feature in ubuntu - but I think its around 185ish.
I might try to compile my own driver and own kde4 from the latest svn, but meh. can´t be arsed.

Dualscreen is vital for me as well.
However, you got to differe if you use one card with dualhead, or 2 cards with singlehead.

With 1 card and both screens connected to it, it should work like a charm just with twinview.
With 2 cards and one screen each card you need xinerama.

I´d wish I could fool around more atm, but I got to blend like hell, tight deadlines.

Estimated project time: 10 Months
Staff needed: 5

Staff available: 1
due: in 5 weeks.

The usual :stuck_out_tongue:

I´ll keep you posted, I plan to compile the nvidia.o tonight and if its not working, try gnome.

from http://ubuntuforums.org/showthread.php?t=221174 is a survey of approachs, and nice little gotcha notes like: here are several known problems with Xinerama. It requires that the physical screens to have the same bit depth. Also in most implementations, OpenGL (3D) direct-rendering only works on one of the screns. Windows that should show 3D graphics on other screens tend to just appear black.

Tried to compile nvidia.o 256.44 in Kubuntu -> failure

Tried Ubuntu.
Firstoff, I got a SIL 5723 pseudoraid controller on my board. the intel sata controller works like a charm, the SIL timed out often because it appears as one port with 2 ports mapped on it. Due to the nature that my intel SATA controller is full, my optical drive is pluged in the SIL. All ACHI is no problem at all, also switching AHCI and IDE back and forth, no trouble.

However for reasons beyond my comprehension, as kubuntu and ubuntu use the same kernel, Kubuntu drops to busybox often after timing out detecting the optical drive, while Ubuntu boots up just nice.

Now for Xinerama.
With one screen on each card, I can only turn on “Seperate X screen” initially. And check xinerama.
-> X starts, nvidia logo shows, X crashes, X restarts… infinite loop of death.

Manually configured both screens to twinview… tadaaa. both work, but with seperate gnomes running. No window swapping between the 2 screens, but I can utilize both at least. I´ll go with this config until that crap is fixed.
srsly. we got the 21st century, how rare is it someone wants to use 2 cards and 2 screens, no wonder linux hardly gets a production environment.
Not to mention the utter PITA to get 5.1 surround running.

If I am in the mood i´ll try twinview + xinerama, but I guess xinerama will crash again.
/var/log/xorg.0.log tells nvidia was unable to find a screen
lies!

Well, no luck so far.

Tried Squeeze (Debian Testing) amd64 today.

x.org + KDE + xinerama = crash
Its either the nvidia.o, x.org or KDE or all together =)

KDE 4.X still is a bird with broken wings.
gnome on the other hand isn´t working properly either.
nvidia don´t really has hobby coders and I tried several driver versions.
x.org shouldn´t be the problem either.

So I account it to user error. Going to keep trying =)
I got a new lead though, I remember that composite + xinerama isn´t working at all. I got no idea though if they fixed it. Going to try lateron.

well absolutely no luck so far.
All surface research lead nowhere and I am not going to dig in xineramas code.

But it seems that the latest xorg has some problems with xinerama which should be fixed soon.
KDE got no idea whats with xinerama, as the developer there maintaining it seems to have no mutli screen setup at all o.O
And gnome, well, at least I get 2 seperate gnome sessions working, not spanning over 2 cards though, maybe with the next xorg update.