Problem with large memory and NIC with a Tyan s4881 thunder k8qw

I recently installed Centos 4.2 on a system with a Tyan S4881 Thunder K8QW motherboard. The system has 4 Optirons with 8gig of RAM and a SATA disk. The motherboard has two integrated NICs.

After installing Centos 4.2, I upgraded the kernel to 2.6.9-34.ELlargesmp, but I am having two *major* problems:

If I let it boot up and access all 8gig of RAM, it complains early in the boot process about a problem with the IOMMU and disables DMA. Later the kernel panics because the IOMMU is disabled. If I limit the memory access to 4gig (mem=4096M), it boots up and runs fine. This is with the 'largemem' kernel.

The second problem is the NICs. They are not seen at all on the PCI bus (lspci does not list them at all).

I have uploaded a collection of files showing the system state:

Length Method Size Ratio Date Time CRC-32 Name -------- ------ ------- ----- ---- ---- ------ ---- 1093 Defl:N 390 64% 04-05-06 17:18 dd33ac17 lsmod 514630 Defl:N 27489 95% 03-27-06 15:21 6b1d8632 lspci 756 Defl:N 255 66% 03-27-06 15:20 b9fd2a94 lspci-tvv 724124 Defl:N 968 plus 185 87% 04-05-06 17:19 03f4def3 messages 114 Defl:N 97 15% 03-27-06 15:20 fb52b0e3 uname -------- ------- --- ------- 1240717 125216 90% 5 files

I spent several *hours* googling for information about this motherboard and the only useful bit on info was that the sata-DMA controller on this motherboard is not able to deal with more than 4gig of RAM, which basically sucks. I guess removing 1-2 of the memory is one solution, but does not help with the problem with the NICs (unless the mem=4096M option affects access to the PCI buses).

Robert Heller -- 978-544-68 plus 133 Deepwoods Software -- Linux Installation and Administration