1. 27 Jun, 2008 1 commit
    • H. Peter Anvin's avatar
      x86: setup: issue a null command after enabling A20 via KBC · aa60d13f
      H. Peter Anvin authored
      Apparently, DOS and possibly other legacy operating systems issued a
      null command to the keyboard controller after toggling A20,
      specifically "pulse output pins" with no output pins specified.  This
      was presumably done for synchronization reasons.  This has made it
      into at least the UHCI spec, and it has been found to cause
      compatibility problems when "legacy USB" is enabled (which it almost
      always is) to not have this byte sent.
      
      It is *NOT* clear if any of these compatibility problems has any
      effect on Linux.  However, for maximum compatibility, issue this null
      command after togging A20 through the KBC.
      Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
      aa60d13f
  2. 31 May, 2008 4 commits
  3. 28 May, 2008 1 commit
  4. 26 May, 2008 12 commits
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  6. 24 May, 2008 6 commits