loadable drivers

[John Hein]

Bernd Walter wrote at 18:21 +0200 on Oct 15, 2008:
 > On Tue, Oct 14, 2008 at 04:32:30PM -0600, John Hein wrote:
 > > M. Warner Losh wrote at 15:34 -0600 on Oct 14, 2008:
 > >  > In message: <20081015003842.a2bd682b.stas at FreeBSD.org>
 > >  >             Stanislav Sedov <stas at freebsd.org> writes:
 > >  > : On Tue, 14 Oct 2008 14:25:32 -0600
 > >  > : John Hein <jhein at timing.com> mentioned:
 > >  > : 
 > >  > : > What needs to be done to support loadable drivers under arm/freebsd?
 > >  > : 
 > >  > : I think they should work, aren't they?
 > >  > 
 > >  > Build them...  They work..
 > > 
 > > Sorry for the poor problem statement.  They do load, but I'm not
 > > getting into the probe or attach.  At first I thought the load
 > > was failing, but that was driver error (pardon the pun).
 > 
 > Then it is likely a driver or configuration specific problem.
 > One of the possible reasons is that you may missing hints, because many
 > devices in embedded systems don't support probing.
 > IIRC I already successfully loaded USB modules on AT91.

Yes, it was my error... missing identify method.  I've been using
drivers parented to self-identifying busses for so long, I forgot
that important little detail.

Sorry for the gross misdirection.

Note that loading the uftdi driver via kldload behaves differently on
arm than when it's compiled into the kernel.  It boils down to
uaa->iface being NULL (in uftdi_match) in the former case and not NULL
in the latter.  I haven't tracked that down yet, but kldload works
fine on x86.