Re: Intel TigerLake NVMe vmd: Adding Support & Debugging a Patch

On Tue, Dec 29, 2020 at 6:30 PM Neel Chauhan <neel_at_neelc.org> wrote:
>
> Hi freebsd-hackers_at_, CC'd freebsd-current_at_,
>
> I hope you all had a wonderful holiday season.
>
> I recently got a HP Spectre x360 13t-aw200 which is an Intel
> TigerLake-based laptop. It has the Intel "Evo" branding and an "Optane"
> SSD which I disabled (so I can get a "second" SSD).
>
> On the Spectre, the NVMe is not detected: https://imgur.com/a/ighTwHQ
>
> I don't know if it is HP or Intel, but the VMD IDs device id is
> 8086:9a0b. I'm guessing Intel since Dell laptops (XPS, Vostro) also have
> this device ID [1].
>
> Sadly, NVMe RAID is forced on this laptop.
>
> I wrote a rough patch to add the device IDs, and the patch is below:

FWIW, that is the same change I would have made. Peeking at the Linux
vmd driver, it doesn't appear to do anything special for 8086:9a0b as
compared to the 8086:2a0c device the FreeBSD driver already supports.
That said, the Linux driver reads a capability register to determine
the bus number start (vmd_bus_number_start()) which I don't see in the
FreeBSD driver. This is curious because, looking at the "lspci all"
output from the XPS link you provided, the NVMe device shows up in PCI
domain 0x1000 (i.e. not 0x0000). Which (and I have no direct
experience with this device or code) only happens if the bus number
start function returns 0x0.

What is the output from
# pciconf -rb pci0:0:14:0 0x40:0x48

--chuck