When to burn those bridges

[M. Warner Losh]

In message: <1063181264.43759.6.camel at herring.nlsystems.com>
            Doug Rabson <dfr at nlsystems.com> writes:
: On Wed, 2003-09-10 at 02:03, M. Warner Losh wrote:
: > If there's a really compelling reason (and this would be it), we can
: > burn some bridges early.  I wouldn't hold up your development based on
: > these bridges being in harm's way.  Others in the BSDcon terminal room
: > are saying "do it now, screw waiting for 6".  If you can get it done
: > and solid, I'd do it before the branch.  The drivers in harm's way
: > either have out of tree replacements, or aren't that important, or
: > need to be redone and this is a good excuse.
: 
: If I commit this work to -current now, it will break ABI compatibility
: with 5.1-RELEASE. When is the ABI for 5.x suppose to be frozen? Does it
: matter if I break the 5.1 ABI in current? For what its worth, this
: change will also make the kobj method dispatch SMP safe (without locks).

We can still break ABI with 5.1 if there's a good reason.  Making
things MP stafe is a good reason.

: > : The same technique could be used to reduce the number of 'converter'
: > : devices.
: > 
: > I like this.  pcic/cbb have similar issues, but the size of the
: > problem is small.
: 
: Its mainly a cosmetic thing but it has always been an irritation to me
: to have these little clusters of devices where there is only one piece
: of hardware, e.g.:
: 
: 	hostb0
: 	 pci0
: 	  pcib1
: 	   pci1
: 	    amdpm0
: 	     smbus0
: 	      smb0
: 
: should become:
: 
: 	pci0
: 	 pci1
: 	  amdpm0

Actually, the bridges do add value, so at least pcib would need to
remain.  I think it would be hard to get rid of them, but there could
easily be something that I'm missing.

Warner