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

Brian Fundakowski Feldman green at
Wed Mar 29 19:22:31 UTC 2006

On Wed, Mar 29, 2006 at 06:41:56AM +0000, Nate Lawson wrote:
> njl         2006-03-29 06:41:56 UTC
>   FreeBSD src repository
>   Modified files:
>     sys/dev/acpica/Osd   OsdHardware.c 
>   Log:
>   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.

Windows 2001 or higher?

Brian Fundakowski Feldman                           \'[ FreeBSD ]''''''''''\
  <> green at                               \  The Power to Serve! \
 Opinions expressed are my own.                       \,,,,,,,,,,,,,,,,,,,,,,\

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