Second GPU does not show up in `lspci`

Question

I switched the second GPU in one of our servers (Ubuntu 12.04.1 LTS). But now lspci only gives one entry:

$lspci | grep -i nvidia
04:00.0 VGA compatible controller: NVIDIA Corporation G94 [Quadro FX 1800] (rev a1)

I already executed sudo update-pciids and re-installed the nvidia dev driver. What other steps can I do?

Solution 1

Could be a hardware issue: The card isn't fully seated, you didn't plug in a cable (power, etc.), the card is defective, the slot is defective, there is some dust in the slot.

Solution 2

(I know the issue did not exist in 2012, but people searching for it may find it)

For me it turned out that once you plug a M.2 SSD, my board disables the second x16 slot (AsRock AB350 Pro4). From the manual:

So make sure, you also check this.

Comments

[Admin]

Why does a server need two graphics cards?

[Admin]

for GPGPU Computing aka CUDA and OpenCL

[Admin]

@Framester How about output of lspci | grep -i vga?

[Admin]

Are you sure this isn't a hardware issue? E.g., is the card fully seated, does the card work, does the slot, did you plug in the power connector... ?

[Admin]

Is the second on-board or another discrete PCB? If it is on-board, it probably disabled itself.

[Admin]

@derobert, your intuition was right. I forgot to attach the fan power cable correctly. Will you repost your comment as a question, so I can accept it?

[Admin]

@Framester posted as an answer now. Glad to have helped.

[Steven C. Howell]

For me it turned out that the second PCIe x16 expansion port is assigned to the second CPU socket (server board) and I did not yet purchase a second CPU (doh!).