X.org 1.5.3: No devices detected when I add Geforce 7900GS to Geforce 8200 mobo

[zbiggy]

I use mainboard: ASRock K10N78FullHD-hSLI R3.0 (Geforce 8200 integrated, MCP78S) with recent bios P1.70.
Everything runs OK till I insert Geforce 7900 GS (G71 [GeForce 7900 GS] (rev a1)) PCI-E card. When Geforce 7900 PCI-E card is inserted I can not run X. The error returned by nvidia X driver 180.37 is: No devices detected. But lspci finds all cards:
02:00.0 VGA compatible controller: nVidia Corporation GeForce 8200 (rev a2) (prog-if 00 [VGA controller])
03:00.0 VGA compatible controller: nVidia Corporation G71 [GeForce 7900 GS] (rev a1) (prog-if 00 [VGA controller])

Console vesafb works.

What I tried:
turn off integrated Geforce 8200 - not possible - no bios option. The framebuffer size can be set to AUTO/or some predefined memory values - no Disable option.

set in BIOS setup options: PGA: (Primary Graphics Adapter) to PCI-E, hSLI: Disabled
result: I can not boot (computer hangs on video bios screen with text: 'Geforce 7900GS VGA BIOS', next screen with mainboard bios is not yet displayed)

set in BIOS setup options: PGA: Integrated, hSLI: Disabled
everything works. X can't start: No devices detected.

set in BIOS setup options: PGA: Integrated, hSLI: 512MB
everything works. X can't start: No devices detected.

set in BIOS setup options: PGA: PCI-E, hSLI: 512MB
everything works. X can't start: No devices detected.

Setting BusID to "PCI3:0:0" or "PCI2:0:0" in xorg.conf returns No device found.

I bought Geforce 8200 to have full hardware VDPAU (which is great) so if nothing can be done let me know so I will sell 7900GS (I like to have powerful 3D but VDPAU rules ).

[AaronP]

The fact that you have to specify a BusID is a bug in the X server. Given that, the syntax is "PCI:x:y:z", not "PCIx:y:z". You can also just write, "x:y:z".

[zbiggy]

Originally Posted by AaronP

The fact that you have to specify a BusID is a bug in the X server. Given that, the syntax is "PCI:x:y:z", not "PCIx:y:z". You can also just write, "x:y:z".

Thank you for reply. Adding missing ':' resolved problem. I have some questions:
1. Do you know if this bug is fixed in 1.6.0 release? (I use 1.5.3 now and looks it is not)
2. Can Nvidia driver 180.37 work with X.org 1.6.0?
3. If not when it will be compatible?
It just came to my mind which might be useful for Nvidia driver: First I put BusID of GF7900 to xorg.conf. It didn't start because there was no monitor connected (reported by Nvidia driver). Then I changed BusID to GF8200 where monitor connected is and everything works. My idea is: Nvidia driver could iterate detected Geforce GPUs and activate the one with connected monitor. This will be user friendly. Especially if second GPU is used for CUDA or other things like SLI.

BTW: It would be nice to have hybrid SLI on Linux. Having such support could save trouble I had in this topic.

Thank you for solving my problem.

[AaronP]

Originally Posted by zbiggy

1. Do you know if this bug is fixed in 1.6.0 release? (I use 1.5.3 now and looks it is not)
2. Can Nvidia driver 180.37 work with X.org 1.6.0?
3. If not when it will be compatible?

1. I don't believe it is.
2. It should.
3. N/A