Cannot use second GPU on 6990

[Forp]

Being a bit deperate at this end...having worked 2 days on my brand new 6990 and unable to use the second GPU.

This is an Athlon x2 on an ASROCK 890 GX Extreme 4 with a Sapphir 6990.

OS is latest Debian 64 bit via netinstall, ATI Driver Package is 11.5, Catalyst is 10.9 and SDK is 2.4

What I get after the usual fighting against docs and google pages is a nice 330 MH/s on a poclbm on device 0, but on device 1 is get the verification error message.

I did check the usual stuff, like DISPLAY to :0 and turning off crossfire and all kinds of things, but it still is the same. I read that most people here are using SDK 2.1 so I tried to downgrade to 2.1 but here I opencl does not see the GPU at all.

Any ideas please?

Or, any confirmation that someone is mining under 6990 and Linux successfully - and could you send some params such as SDK versions, driver versions and stuff you had to do...

Since I am looking forward to upgrade this to a 3x 6990, Windows is not really an option due to the 4 GPU limitation.

Best,
Forp.

[nakowa]

Me too.

Ubuntu 11.04, Radeon HD 6990

When I open second miner trying to use device 1, computer halt...

[Calavera]

Most people aren't using 6990s.  It took me a while to realise that.  The older drivers don't work with the cayman based cards.

I don't think I know the "verification error message".  I was running Ubuntu 11.04 and didn't the same problems as you.

Did you get the catalyst drivers from the AMD website or via apt?

[Forp]

The older drivers don't work with the cayman based cards.

Did you get the catalyst drivers from the AMD website or via apt?

I am using the catalyst drivers from the AMD website. Are you using the apt version?

I don't think I know the "verification error message".  I was running Ubuntu 11.04 and didn't the same problems as you.

to me it looks like the second device does not do any calculation at all. At least: The "verification error message" is triggered when a rough plausibility check of the results shows some bits to be zero which should not be zero. It looks like the driver ignores the params to the GPU and just returns default or zero results even without proper error message.

However: There are miners using more than 2 odr even 3 6990 GPUs so I assume there is a trick. 

[Calavera]

Okay, so the verification error is from Phoenix rather than from the driver via Phoenix?

Unfortunately I was using the same drivers as you.   However, I was using Ubuntu 11.04 rather than Debian.  I had two 6990s and all four GPUs worked.

I created a fresh install and more or less followed Inaba's guide: http://forum.bitcoin.org/?topic=7514.0 (he has changed it since, it didn't fully work at the time and he didn't have the 2.4 instructions) except I dropped fglrx from apt-get and got the 11.5 driver directly from AMD (and just ran it via "sudo sh driver.run" rather than following https://help.ubuntu.com/community/BinaryDriverHowto/ATI which turns it into a package first). 

You might want to consider sticking windows on the machine to make sure the card actually works.