Bjørn Mork bjorn at mork.no
Sat Aug 24 13:26:48 UTC 2019

Sk8teboardingboy <sk8teboardingboy at gmail.com> writes:

> I am sure that you are aware the new modem including those 5G modems
> will only support PCIe interface to the host PC,

No, not really.  Where did you get this info?

> is there a plan from this group to tackle this new interface to
> continue the MBIM support?

MBIM is a USB device class spec.  When you say "PCIe MBIM", then you
have a large black box between the PCIe host bus and this USB device.
The existing (Windows) driver I've seen creates a virtual USB device,
implementing the MBIM device side inside the driver. Which makes sense.
But writing such a driver is a lot of work.  And it's "impossible"
unless you have docs for the proprietary PCIe interface.  AFAIK, no
vendor has made such docs available.

Which probably doesn't matter anyway.  I don't know of anyone who would
want to invest that much work into supporting a single vendor
proprietary solution.  But there are lots of crazy folks out there, so
who knows?  :-)

Anyway, the PCIe interface seems to be chosen to make modem interfaces
proprietary and still sort-of meet the Windows certification
requirements. I see no sane reason to drop USB.  Let's hope Microsoft
closes this hole before the problem escalates.  They did a very good job
with the MBIM requirement for Windows 8.  Let's hope they can push back
this time too.


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