X can't handle two dual-head nvidia cards

[Pavel Pergamenshchik]

Binary package hint: xserver-xorg

I have two PCI Express nVidia cards, a 7900GT with one LCD, and a 6800GT with two CRTs. There's a bug in X config parser that prevents it from using the second CRT. I'm using Edgy, but this has been broken since XFree86.

[Pavel Pergamenshchik (ppergame)]

I created three Device sections, one for PCI:5:0:0, and two for PCI:4:0:0.

[Pavel Pergamenshchik (ppergame)]

Note the "(WW) NVIDIA: No matching Device section for instance (BusID PCI:4:0:0) found" -- that's when X tries to match Device sections with the hardware it found.

[Pavel Pergamenshchik (ppergame)]

(it's probably not specific to nvidia)
I have two cards, a 7900GT with an LCD and and a with two CRTs. I defined three
device sections (specfying BusID), however X fails to use one of the CRTs. The
error message is "(WW) NVIDIA: No matching Device section for instance (BusID
PCI:4:0:0) found".

Further investigation points at xf86MatchPciInstances(), a heap of incorrect
flaming crap. The way it matches Device sections and PCI devices is completely
broken, at least with my hardware.

Config and output are at
http://librarian.launchpad.net/4244751/xorg.conf
http://librarian.launchpad.net/4244753/Xorg.0.log

[Pavel Pergamenshchik (ppergame)]

fx86MatchPciInstances is innocent, in this case.
nvidia_drv calls xf86SetEntityInstanceForScreen with
(<screen0>, 0, 0)
(<screen1>, 1, 0)
(<screen2>, 1, 1)
I think the last argument, instance, should be 1 and 2 in the last two calls. Is
that true?

[Imbezol (imbezol)]

I can't add any insight into the problem but I can confirm I have the same issue.

I have an nVidia GeForce 7900 GT which runs my middle monitor, and an nVidia
GeForce 6600 which drives my two side monitors. All three monitors are NEC FE950
19" CRT displays. The right monitor displays gibberish with the nv driver.

http://imbezol.org/misc/xorg.conf.nv

[Daniel Stone (daniels)]

Sorry about the phenomenal bug spam, guys. Adding xorg-team@ to the QA contact so bugs don't get lost in future.

[Pavel Pergamenshchik (ppergame)]

Someone in #xorg told me about a workaround a while ago. In 6800GT_2's Device section, change "Screen 2" to "Screen 0". It sounds entirely too stupid, but it works.

[Ambricka (petter-ambricka)]

This problem seems to have been fixed, and now came back with intrepid.

I had two nVidia quadro fx570 cards which worked until intrepid, when the x-server couldn't decide wich device to use, and claimed "no devices found".
The only solution we've found so far is to pull out one of the cards.

[Manuel Werlberger (mwerlberger)]

Same Problem here. I have a 8600 as 'main' card for XOrg and a 280GTX for CUDA calculations. With both cards plugged in the XOrg log tells me that it cannot find a device. With either one of the cards it works out of the box.

[Manuel Werlberger (mwerlberger)]

For me nvidia-xconfig -a solves the problem - Again Xorg running with both cards available...

[Timo Aaltonen (tjaalton)]

I'm closing this one if the issue used to work before intrepid. The new bug is bug 267241.

[Anton Patsev (patsev-anton)]

Pavel Pergamenshchik
Do you still experience this issue with newer soft ?
Please check the status of your issue.

[Ajax-a (ajax-a)]

MatchPciInstances is still not great, but the code _has_ changed significantly since 2006, so this probably isn't a useful report of that fact.