ACK: [SRU] [OEM-B] [PATCH 0/2] Use "Medium power with Device Initiated PM" as default LPM policy for mobile SATA devices

[Anthony Wong]

On Thu, Jun 21, 2018 at 05:59:16PM +0800, Kai-Heng Feng wrote:
> BugLink: https://bugs.launchpad.net/bugs/1778029
> 
> [Impact]
> Intel CPU can't reach beyond Package C-State 3 (PC3). Drains lots of power.
> 
> [Test]
> Check the value of /sys/devices/pci0000:00/0000:00:17.0/ata1/host0/scsi_host/host0/link_power_management_policy.
> 
> It's med_power_with_dipm as default.
> Also check the powertop, it can reach PC8.
> 
> [Fix]
> Introduce a new config to let AHCI pick med_power_with_dipm for mobile platforms.
> 
> [Regression Potential]
> Medium. Some SATA devices are broken under med_power_with_dipm or min_power.
> Fortunately this is for -oem kernel only, so every SATA device gets tested before shipping to customers.
> 
> Hans de Goede (1):
>   ahci: Allow setting a default LPM policy for mobile chipsets
> 
> Kai-Heng Feng (1):
>   UBUNTU: Config: set CONFIG_SATA_MOBILE_LPM_POLICY to
>     med_power_with_dipm
> 
>  debian.oem/config/config.common.ubuntu |  1 +
>  drivers/ata/Kconfig                    | 19 +++++
>  drivers/ata/ahci.c                     | 97 +++++++++++++++-----------
>  drivers/ata/ahci.h                     |  3 +
>  4 files changed, 79 insertions(+), 41 deletions(-)
> 
> -- 
> 2.17.0

Looks good, med_power_with_dipm has gone through some testing in the
public lately, and as it is for linux-oem only the scope is limited
and we can catch any side-effects in our QA process.

Signed-off-by: Anthony Wong <anthony.wong at canonical.com>