[SeaBIOS] SeaBIOS recognising USB 3.0 on boot works - partly

[Kevin O'Connor]

On Sat, Dec 19, 2015 at 01:11:34AM +0100, Peter Stuge wrote:
> Kevin O'Connor wrote:
> > > > > Would checking the connection status for each device after all
> > > > > devices have been registered be able to filter the USB2 device out?
> > > > 
> > > > Yes, but there isn't a way to "unregister" the drive once it's been
> > > > registered.
> > > 
> > > Oh - why not?
> > > 
> > > If this has to do with e.g. BBS then maybe first register internally
> > > during probing, then filter disconnected devices out, *then* register
> > > "for real" ?
> > 
> > Doing that is equivalent (unless I've missed something) to delaying
> > registration until detection completes on all other ports on that
> > controller.  That's the delay I'm leery of adding.
> 
> Hm - maybe I'm missing something?
> 
> Doesn't it effectively take the same amount of wall clock time?

Delaying registration vs unregistering would (I believe) take the same
wall clock time.

If you're asking if current state vs unregistering/delaying would take
the same wall time - thinking about that now, it might be true.  I
guess the implementaiton and how things like CONFIG_THREADS=n are
handled would determine that.

> Is your worry that by postponing registration some oddities could
> come up e.g. in option ROMs that also parse the boot device list?

No.

> I looked at the code - technically it seems straightforward to
> implement a boot_remove_hd(). Is that disallowed by the BBS?

That's not my concern.  I think it would be confusing to add and then
remove.  Simpler to only add when we know it's real.

-Kevin