Re: [PATCH 1/4] PCI / ACPI: Identify external PCI devices

[Mika Westerberg]

On Fri, Nov 16, 2018 at 01:18:04AM -0800, Christoph Hellwig wrote:
> On Thu, Nov 15, 2018 at 09:10:26PM +0200, Mika Westerberg wrote:
> > FireWire is kind of different but there are connectors such as
> > ExpressCard and NVMe (over U.2 connector) which carry PCIe and are
> > relatively easy to access without need for a screwdriver. AFAIK some
> > eGPUs are also using some other proprietary (non-TBT) connector that
> > carries PCIe.
> 
> U.2 is a data center internal form factor with hot plug capability. If
> you enable an iommu for that by default you will make a lot of people
> very unhappy.

Well, it needs the other bit in ACPI DMAR table to be enabled by default
so I don't think anyone in data center domain will notice ;-)

> More importantly NVMe is now used for the current/next generation
> Compact Flash and SD cards, which contain full PCIe gen 3 links.

OK, thanks for the information - I did not know that. I guess those
belong to the "external" category as well.