Dell XPS 8940 SATA and NVMe disk controller not recognized

[Karl Dunn]

I have new Dell XPS 8940 that came with Windows 10 Home installed.  I have 
created two partitions for FreeBSD, one on its NMVe 256GB SSD, and one on 
its WD 1TB HD.

For now, I have 12.2-RELEASE-p4 GENERIC on a USB memstick, so I can do 
some limited testing.

FreeBSD 12.2 does not recognize the SATA/RAID controller, which I assume 
is resposible (in Win10) for accising both drives.

The relevant pcoconf line for the controlleris:

  none7 at pci0:0:23:0: class=0x010400 card=0x09c51028 chip=0x06d68086 rev=0x00 hdr=0x00
     vendor     = 'Intel Corporation'
     class      = mass storage
     subclass   = RAID

Because no net devices work (for FreeBSD), I put a pcie-x1 net card in the 
machine to get access, 15 bucks to Ebay, works great.  I can't get the 
NVIDIA graphics card to work right, but that and the net devices are 
issues for sometime later.

Here is a URL for info I collected from the machine, including from the 
hw-probe utility:

   http://home.hiwaay.net/~kldunn/XPS_8940_info.html

That has a link for the results of hw-probe, the outputs of pciconf -lv 
and dmesg, and the content of /var/log/messages and rc.conf.

The hw-probe report claims that Linux supports the SATA/RAID controller in 
'drivers/ata/ahci.c', but that no version of FreeBSD knows about it (yet).

I think FreeBSD might need a patch to sys/dev/ahci/ahci_pci.c, and maybe 
some other files too.

Can somebody help me with disk access?

  --
Karl L. Dunn
kldunn at hiwaay.net