• H. Peter Anvin's avatar
    x86: attempt reboot via port CF9 if we have standard PCI ports · 14d7ca5c
    H. Peter Anvin authored
    Impact: Changes reboot behavior.
    
    If port CF9 seems to be safe to touch, attempt it before trying the
    keyboard controller.  Port CF9 is not available on all chipsets (a
    significant but decreasing number of modern chipsets don't implement
    it), but port CF9 itself should in general be safe to poke (no ill
    effects if unimplemented) on any system which has PCI Configuration
    Method #1 or #2, as it falls inside the PCI configuration port range
    in both cases.  No chipset without PCI is known to have port CF9,
    either, although an explicit "pci=bios" would mean we miss this and
    therefore don't use port CF9.  An explicit "reboot=pci" can be used to
    force the use of port CF9.
    Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
    14d7ca5c
reboot.c 14.3 KB