Olivier Langlois's blog

lano1106@whippet2 ~ $ aticonfig --adapter=0 --crossfire=on
Crossfire chain(s) enabled
CrossFire does not support on this platform
Warning: X needs to be restarted before CrossFire changes take effect.


When you get the message "CrossFire does not support on this platform", CrossFire is not enabled. I wish the error would be more verbose than that but I think that I have good lead to investigate:

lano1106@whippet2 ~ $ lsmod | grep fglrx
Module Size Used by
fglrx 5176689 203
amd_iommu_v2 7252 1 fglrx
button 4669 1 fglrx


The interesting info here is that amd_iommu_v2 is used by fglrx and


lano1106@whippet2 ~ $ dmesg | grep IOMMU
[ 2.614901] AMD IOMMUv2 driver by Joerg Roedel <joerg.roedel@amd.com>
[ 2.614902] AMD IOMMUv2 functionality not available on this system


I'll investigate the situation further but it makes sense that the AMD IOMMU does not work on my Intel board (ASUS P9X79 WS). The concept of IOMMU is totally new to me and still a bit fuzzy but apparently is provided by Intel through VT-d that you normally enable by:

1. Turn it on from the bios
2. Add the kernel param intel_iommu=on