Two SCSI controllers with 4.10-STABLE?

[Scott Long]

Michael L. Squires wrote:
> 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

Are you sure that the drives are being discovered in the correct order? 
  You might need to re-arrange the drives on each bus or 'wire' down the
order in the kernel config file.  See /sys/i386/conf/LINT for details on
how to do this.

Scott