cvs commit: src/sys/dev/acpica/Osd OsdHardware.c

Nate Lawson njl at
Wed Mar 29 06:41:56 UTC 2006

njl         2006-03-29 06:41:56 UTC

  FreeBSD src repository

  Modified files:
    sys/dev/acpica/Osd   OsdHardware.c 
  Add a blacklist for bad IO ports that AML should never touch.  It seems
  some systems were designed so that AML writes to various resources shared
  with OS drivers, including the RTC, PIC, PCI, etc.  These writes could
  collide with writes by the OS and should never be performed.  For now, we
  print a message if such an access occurs, but do not block it.  To block
  the access, the tunable "debug.acpi.block_bad_io" can be set to 1.  In the
  future, we will flip the switch and this will become the default.
  Information about this problem was found in Microsoft KB 283649.  They
  block IO accesses if the BIOS indicates via _OSI that it is Windows 2001
  or higher.  They always block accesses to the PIC, cascaded PIC, and ELCRs,
  no matter how old the BIOS.
  Revision  Changes    Path
  1.18      +76 -0     src/sys/dev/acpica/Osd/OsdHardware.c

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