1

Background.

I got a problem installing (K)ubuntu yesterday. It started well with the Kubuntu 13.04 installer recognizing my 3 screens out of the box for the splash screen: pic1. However, after that, the installer screen turns up either black or garbled, but with a perfectly working (perfectly shaped & colored, moving, changing on hover...) mouse pointer. pic2

I can't see what I click on, but if I click on the place where I know "Try Kubuntu" should be, it changes to pic3 and also the non-graphical interface (like a tty terminal) works flawlessly. So the problem is purely with the graphics.

My question.

Why does this happen? And more importantly, how can I obtain a working Kubuntu installation with working graphics, with my current hardware (see below)?

What I have tried (and how it worked).

  • Naturally, I suspected to be the triple screens to be the problem. But exactly the same behavior appears on 1 screen, so it's not related to this.
  • I tried with Kubuntu 12.04 LTS, as that has an older graphics drivers, but to no avail: indeed the startup window shows (on only 2 screens), but actually trying Kubuntu brings me to pic4, which after 5 minutes of stalling falls back to pic5 and stays there forever.
  • Thinking it might be Kubuntu-specific, I tried the regular Ubuntu 13.04. To no avail, same behaviour: splash screen works on all 3 screens, then it turns black with working cursor (this time moving freely over all screens though).
  • If I remove all GPUs but the first, then everything works flawlessly out of the box pic6 but since the purpose of this computer was exactly to have a GPGPU machine, using only one GPU is not an option. And only the first GPU is responsible for the graphics anyway so it's a mystery to my why Kubuntu even touches these secondary cards (without screens attached). None of the cards is broken, all cards work flawlessly if they are placed as first and only GPU.
  • Adding or removing the CrossFire bridges between the cards has no effect on the problem.

Relevant hardware specifications.

  • EVGA Z77 FTW motherboard (intel i7-2600K CPU, 16GB RAM)
  • 3x Radeon HD 7970 GPU (all screens connected to first GPU, removing CrossFire bridges changes nothing)
  • 1200W power supply (much more than ever needed under full load, so that's not the problem.

I cannot see how any other specifications could matter, but feel free to ask if anyone thinks more info could be useful. For a final picture: pic7

Thanks in advance!

  • Nice Hardware - The only thing I can think of is to install it with all hardware, then use another computer to SSH into it and remove relevant Radeon external GPU drivers as root - you could then see if you could find a better alternative. It may be using the open-source radeon driver, and may work better with the propratry drivers - fglrx or catalyst - see here (May not be the best of links). Anyway, what could you possibly use 3 GPUs for? :-) – Wilf Nov 27 '13 at 21:15
  • Afterthought: blacklisting the driver would be a lot better than removing it - see here. – Wilf Nov 27 '13 at 22:19

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