MFC r221712:

MFC r221712:
  Since r117657, bge(4) does not enable buffer manager for BCM5705 or
  newer controllers.  However, all data sheet I have access has no
  indication that buffer manager should not be touched on these
  controllers.  It seems the buffer manager always runs on BCM5705 or
  newer controllers. Some controller(e.g. BCM5719) needs other buffer
  manager configuration so driver should enable buffer manager for
  all controllers.  Both Linux and OpenBSD/NetBSD use the same
  approach.
  This change polls enable bit of block to know whether specified
  block was really stopped as well as enabling buffer manager for all
  controllers in driver initialization.

  Obtained from:	NetBSD

git-svn-id: svn://svn.freebsd.org/base/stable/8@222369 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f