Two SCSI controllers with 4.10-STABLE?

[Michael L. Squires]

This question relates to 4.10-STABLE.

I had to reuse the motherboard in my home server, a SM P6DGH with onboard 
dual-channel SCSI, with an older P6DLH which does not have onboard SCSI. 
The P6DGH had 5 SCSI drives on channel A, and 4 on channel B.  I installed 
two LSI/Symbios 875 SCSI controllers on the P6DLH.  There were no problems 
as long as all 9 drives were on one controller, but if I tried to spread 
the drives across two controllers the system would boot but fail to mount 
the root partition, complaining that it couldn't be found.  I replaced 
the two 875's with two 2940UW's - same problem.  There were no problems
detectable using the onboard diagnostics, all 9 drives were recognized
in the right places, as were the controllers.

I know I had a P6DLH with two 2944UW's and one 2940UW, with HVD SCSI disks 
on both 2944UW's, so I know it's possible - my memory is that this was 
3-STABLE.

I know I must be missing something simple, but I don't know what it is. 
The disks aren't very fast, and the load is light, so using only one 
controller is not a real problem - but with 8 empty PCI slots and spare 
controllers it just bothers me.

Mike Squires