Issue with finding net port for a MBIM modem

[Dan Williams]

On Fri, 2017-08-18 at 22:09 +0200, Aleksander Morgado wrote:
> > > But now I wonder, maybe we could just remove the whole block? Is
> > > there
> > > any case nowadays were we don't get port event removals? If this
> > > was a
> > > hack for a bug in kernel 2.6.31, maybe we could consider it
> > > already
> > > obsoleted?
> > 
> > 
> > 
> > Yeah, this comes from an old commit
> > 53af144f49b0d81bd4dc1f5ee9eea6d61ccae992
> > (udev: handle removal of parent usb devices) dated back to 2009,
> > which seems
> > to imply that the kernel doesn't remove the tty when the usb device
> > is
> > removed. I guess it's probably not hard to reproduce the steps, but
> > I'm not
> > sure if the original fix was related to a particular kernel version
> > or a
> > particular devices or a combination of both.
> > 
> 
> Dan, what do you think?
> 
> From my POV, I would nuke that device removal logic right away now...

I'll have to think about that one, but I'm on vacation all this coming
week so I might not have a reply soon.  IIRC it may have been related
to before the tty subsystem was fully sysfs/kevent ported.  I think we
could be reasonably sure about it if we test a bunch of old modems with
the block removed.

Dan