cvs commit: src/sys/i386/acpica madt.c

[John Baldwin]

jhb         2004/04/16 12:46:30 PDT

  FreeBSD src repository

  Modified files:
    sys/i386/acpica      madt.c 
  Log:
  Revert part of the "BIOS brain damage" from rev 1.10.  It seems that
  different BIOSs use the same exact settings to mean two very different and
  incompatible things for the SCI.  Thus, if the SCI is remapped to a PCI
  interrupt, we now trust the trigger/polarity that the MADT provides by
  default.  However, the SCI can be forced to level/lo as 1.10 did by setting
  the tunable "hw.acpi.force_sci_lo" to a non-zero value from the loader.
  
  Thus, if rev 1.10 caused an interrupt storm, it should nwo fix your
  machine.  If rev 1.10 fixed an interrupt storm on your machine, you
  probably need to set the aforementioned tunable in /boot/loader.conf to
  prevent the interrupt storm.
  
  The more general problem of getting the SCI's trigger/polarity programmed
  "correctly" (for some value of correctly meaning several workarounds for
  broken BIOSs and inconsistent "implementations" of the ACPI standard) is
  going to require more work, but this band-aid should improve the current
  situation somewhat.
  
  Requested by:   njl
  
  Revision  Changes    Path
  1.11      +5 -4      src/sys/i386/acpica/madt.c