Dual ATI cards cause X failure on fglrx installation

[Mark Shuttleworth]

I installed Ubuntu 8.10 on a new machine that has dual ATI cards. It prompted me to install the proprietary fglrx driver, which I did. On reboot, X failed.

Examinging xorg.0.log I saw a comment that X could not decide which card was primary. I found the Device section of xorg.conf, where the Driver "fglrx" had been put, and added a line like:

   BusID "PCI:1:0:0"

X now correctly starts up.

I think it was a lucky guess, I haven't tested what would have happened if I'd used the BusID of the OTHER ATI card, but I'm guessing that X would have brought up the server on that other card, with undetermined results for the monitor I was looking at. I don't know if it is possible to detect from a script (a) if there are multiple ATI cards and (b) which one of them currently has a monitor attached, but if it is, then we should detect that and ensure that xorg.conf includes the right BusID.

In future, I'm sure X will handle this situation better!

[Mario Limonciello (superm1)]

This is likely a situation similar to bug 267241, but since the circumstances are a little bit different it might not actually be a duplicate. It's possible that you just got "lucky" that X started up the first time (or few times) by picking the correct card.

Could you add your Xorg log and lspci -vvnn to this bug for some further evaluation to determine if it's a duplicate of that X bug or something wrong with fglrx?

Ideally if you can add an X log both with that BusID line and without, that would be best.

[Mark Shuttleworth (sabdfl)]

Yes, this is a dup of #267241, thanks for spotting that Mario!

My log has these lines:

(!!) More than one possible primary device found
(--) PCI: (0@1:0:0) ATI Technologies Inc R600 [Radeon HD 2900 Series] rev 0, Mem
 @ 0xc0000000/0, 0xfcce0000/0, I/O @ 0x0000a000/0, BIOS @ 0x????????/131072
(--) PCI: (0@2:0:0) ATI Technologies Inc R600 [Radeon HD 2900 Series] rev 0, Mem
 @ 0xd0000000/0, 0xfcde0000/0, I/O @ 0x0000b000/0, BIOS @ 0x????????/131072

and later:

Fatal server error:
no screens found

So I will mark it a dup of the previous report, and subscribe there.