git: acpi/pcib: Rework the _BBN handling for Host-PCI bridges.

[Sepherosa Ziehau]

commit 6b7d068d64b43c22bd94780672ee429baa09e8c0
Author: Sepherosa Ziehau <sephe at dragonflybsd.org>
Date:   Thu Apr 7 18:11:16 2011 +0800

    acpi/pcib: Rework the _BBN handling for Host-PCI bridges.
    
    Obtained-from: FreeBSD (Revision 193829 by jhb at freebsd.org)
    
      Previously we only trusted a _BBN value of 0 if it was for the first
      bridge encountered since some older systems returned _BBN of 0 for
      all bridges.  However, some newer systems enumerate bridges with
      non-zero _BBN before bus 0 which is perfectly valid.  Handle both
      cases by trusting the first bridge that has a _BBN of 0 and falling
      back to reading from non-standard config registers only for
      subsequent bridges with a _BBN of 0.  We also only perform this
      check for segment (domain) 0.  We assume that _BBN is always correct
      for segments other than 0.

Summary of changes:
 sys/dev/acpica5/acpi_pcib_acpi.c |   44 ++++++++++++++++++++++---------------
 1 files changed, 26 insertions(+), 18 deletions(-)

http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/6b7d068d64b43c22bd94780672ee429baa09e8c0


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