Use med_power_with_dipm SATA LPM to save more power for mobile platforms

[Kai-Heng Feng]

In order to let CPU Package gets deeper C-state, we need to use power-saving SATA LPM to achieve that.

This commit introduce a new config, SATA_MOBILE_LPM_POLICY:

commit ebb82e3c79d2a956366d0848304a53648bd6350b
Author: Hans de Goede <email address hidden>
Date: Mon Dec 11 17:52:16 2017 +0100

    ahci: Allow setting a default LPM policy for mobile chipsets

    On many laptops setting a different LPM policy then unknown /
    max_performance can lead to power-savings of 1.0 - 1.5 Watts (when idle).

    Modern ultrabooks idle around 6W (at 50% screen brightness), 1.0 - 1.5W
    is a significant chunk of this.

    There are some performance / latency costs to enabling LPM by default,
    so it is desirable to make it possible to set a different LPM policy
    for mobile / laptop variants of chipsets / "South Bridges" vs their
    desktop / server counterparts. Also enabling LPM by default is not
    entirely without risk of regressions. At least min_power is known to
    cause issues with some disks, including some reports of data corruption.

    This commits adds a new ahci.mobile_lpm_policy kernel cmdline option,
    which defaults to a new SATA_MOBILE_LPM_POLICY Kconfig option so that
    Linux distributions can choose to set a LPM policy for mobile chipsets
    by default.

    The reason to have both a kernel cmdline option and a Kconfig default
    value for it, is to allow easy overriding of the default to allow
    trouble-shooting without needing to rebuild the kernel.

    Signed-off-by: Hans de Goede <email address hidden>
    Signed-off-by: Tejun Heo <email address hidden>

"3 => Medium power with Device Initiated PM enable" is a well-balanced that can let Package enters deeper C-state.

Also, Fedora already set SATA_MOBILE_LPM_POLICY=3 for their latest kernel.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1759547

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 4.17.0-6.7

---------------
linux (4.17.0-6.7) cosmic; urgency=medium

  * linux: 4.17.0-6.7 -proposed tracker (LP: #1783396)

  * [Regression] EXT4-fs error (device sda2): ext4_validate_block_bitmap:383:
    comm stress-ng: bg 4705: bad block bitmap checksum (LP: #1781709)
    - SAUCE: Revert "UBUNTU: SAUCE: ext4: fix ext4_validate_inode_bitmap: comm
      stress-ng: Corrupt inode bitmap"
    - SAUCE: ext4: check for allocation block validity with block group locked

  * Cosmic update to 4.17.9 stable release (LP: #1783201)
    - userfaultfd: hugetlbfs: fix userfaultfd_huge_must_wait() pte access
    - mm: hugetlb: yield when prepping struct pages
    - mm: teach dump_page() to correctly output poisoned struct pages
    - PCI / ACPI / PM: Resume bridges w/o drivers on suspend-to-RAM
    - ACPICA: Drop leading newlines from error messages
    - ACPI / battery: Safe unregistering of hooks
    - drm/amdgpu: Make struct amdgpu_atif private to amdgpu_acpi.c
    - tracing: Avoid string overflow
    - tracing: Fix missing return symbol in function_graph output
    - scsi: sg: mitigate read/write abuse
    - scsi: aacraid: Fix PD performance regression over incorrect qd being set
    - scsi: target: Fix truncated PR-in ReadKeys response
    - s390: Correct register corruption in critical section cleanup
    - drbd: fix access after free
    - vfio: Use get_user_pages_longterm correctly
    - ARM: dts: imx51-zii-rdu1: fix touchscreen pinctrl
    - ARM: dts: omap3: Fix am3517 mdio and emac clock references
    - ARM: dts: dra7: Disable metastability workaround for USB2
    - cifs: Fix use after free of a mid_q_entry
    - cifs: Fix memory leak in smb2_set_ea()
    - cifs: Fix slab-out-of-bounds in send_set_info() on SMB2 ACE setting
    - cifs: Fix infinite loop when using hard mount option
    - drm: Use kvzalloc for allocating blob property memory
    - drm/udl: fix display corruption of the last line
    - drm/amdgpu: Add amdgpu_atpx_get_dhandle()
    - drm/amdgpu: Dynamically probe for ATIF handle (v2)
    - jbd2: don't mark block as modified if the handle is out of credits
    - ext4: add corruption check in ext4_xattr_set_entry()
    - ext4: always verify the magic number in xattr blocks
    - ext4: make sure bitmaps and the inode table don't overlap with bg
      descriptors
    - ext4: always check block group bounds in ext4_init_block_bitmap()
    - ext4: only look at the bg_flags field if it is valid
    - ext4: verify the depth of extent tree in ext4_find_extent()
    - ext4: include the illegal physical block in the bad map ext4_error msg
    - ext4: clear i_data in ext4_inode_info when removing inline data
    - ext4: never move the system.data xattr out of the inode body
    - ext4: avoid running out of journal credits when appending to an inline file
    - ext4: add more inode number paranoia checks
    - ext4: add more mount time checks of the superblock
    - ext4: check superblock mapped prior to committing
    - HID: i2c-hid: Fix "incomplete report" noise
    - HID: hiddev: fix potential Spectre v1
    - HID: debug: check length before copy_to_user()
    - HID: core: allow concurrent registr...

[Brad Figg (brad-figg)]

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-bionic' to 'verification-done-bionic'. If the problem still exists, change the tag 'verification-needed-bionic' to 'verification-failed-bionic'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Andy Whitcroft (apw)]

This bug was erroneously marked for verification in bionic; verification is not required and verification-needed-bionic is being removed.