[PATCH v2 0/2] ata: ahci: Enable DEVSLP by default on SLP_S0 support

[Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>]

One of the requirement for modern x86 system to enter lowest power mode
(SLP_S0) is SATA IP block to be off. This is true even during when
platform is suspended to idle and not only in opportunistic (runtime)
suspend.
This series is to enable DEVSLP by default.

v2:
 As suggested by Hans, take care of the module param is same as default
 LPM policy

-current (non-rfc) series
Implemented suggestions from Hans
- no override of policy set via module param
- Override lpm policy per host not global policy
- changed the new policy name to "min_power_with_partial"

rfc-v2
- As suggested by Hans, it is possible to have ASP with DEVSLP, so
add a new state.
- Removed usage of mem_sleep_current, instead just rely on low power
idle flag. Don't feel good to EXPORT from core suspend code.
- Depending host policy to decide if we enable DEVSLP by default.

Srinivas Pandruvada (2):
  ata: ahci: Support state with min power but Partial low power state
  ata: ahci: Enable DEVSLP by default on x86 with SLP_S0

 drivers/ata/ahci.c        | 38 +++++++++++++++++++++++++++++++++-----
 drivers/ata/libahci.c     |  5 ++++-
 drivers/ata/libata-core.c |  1 +
 drivers/ata/libata-scsi.c |  1 +
 include/linux/libata.h    |  3 ++-
 5 files changed, 41 insertions(+), 7 deletions(-)

-- 
2.17.1