• Kristen Carlson Accardi's avatar
    [libata] AHCI: add hw link power management support · 31556594
    Kristen Carlson Accardi authored
    This patch will set the correct bits to turn on Aggressive
    Link Power Management (ALPM) for the ahci driver.  This
    will cause the controller and disk to negotiate a lower
    power state for the link when there is no activity (see
    the AHCI 1.x spec for details).  This feature is mutually
    exclusive with Hot Plug, so when ALPM is enabled, Hot Plug
    is disabled.  ALPM will be enabled by default, but it is
    settable via the scsi host syfs interface.  Possible
    settings for this feature are:
    Setting         Effect
    min_power       ALPM is enabled, and link set to enter
                    lowest power state (SLUMBER) when idle
                    Hot plug not allowed.
    max_performance ALPM is disabled, Hot Plug is allowed
    medium_power    ALPM is enabled, and link set to enter
                    second lowest power state (PARTIAL) when
                    idle.  Hot plug not allowed.
    Signed-off-by: default avatarKristen Carlson Accardi <kristen.c.accardi@intel.com>
    Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
ahci.c 62.8 KB