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Subject[PATCH v3 0/7] Runtime PM for Thunderbolt on Macs
Power down Thunderbolt controllers on Macs when nothing is plugged in
to save around 2W per controller.

Apple provides an ACPI-based (but nonstandard) mechanism to cut power
and signal hotplug during powerdown. The usual way to implement such
nonstandard mechanisms seems to be a struct dev_pm_domain.
E.g. vga_switcheroo uses that for Optimus GPUs which control power
with ACPI DSMs. Hence this third iteration of the series uses that
as well. In v2 a more complicated approach was employed wherein power
control was exerted by a PCIe port service driver instead.

All the prep work went into 4.9 and 4.10, shrinking this series to just
7 patches:

- The actual "meat" of the series (to borrow a term from Bjorn) is in
patches [6/7] and [7/7]. These two need an ack from Andreas.

- Patches [1/7] to [3/7] need an ack from Bjorn (and possibly Rafael or
Mika). They're fairly small and just add a bit to struct pci_dev
signifying that a device is part of a Thunderbolt daisy chain, then
use that bit to modify runtime PM for PCIe ports. I'm also cc'ing
Tomas and Amir at Intel Israel, if you guys have comments please shout.

- Patches [4/7] and [5/7] need an ack from Rafael. Their sole purpose
is to avoid a gratuitous WARN splat when assigning the struct

I've pushed the patches to GitHub to ease reviewing/fetching:

Link to the previous iteration (v2, May 2016):



Lukas Wunner (7):
PCI: Recognize Thunderbolt devices
PCI: Allow runtime PM on Thunderbolt ports
PCI: Don't block runtime PM for Thunderbolt host hotplug ports
Revert "PM / Runtime: Remove the exported function
PM: Make requirements of dev_pm_domain_set() more precise
thunderbolt: Power down controller when idle
thunderbolt: Runtime suspend NHI when idle

drivers/base/power/common.c | 15 +-
drivers/base/power/runtime.c | 3 +-
drivers/pci/pci.c | 20 ++-
drivers/pci/pci.h | 2 +
drivers/pci/probe.c | 34 +++++
drivers/thunderbolt/Kconfig | 3 +-
drivers/thunderbolt/Makefile | 4 +-
drivers/thunderbolt/nhi.c | 5 +
drivers/thunderbolt/power.c | 356 +++++++++++++++++++++++++++++++++++++++++++
drivers/thunderbolt/power.h | 37 +++++
drivers/thunderbolt/switch.c | 9 ++
drivers/thunderbolt/tb.c | 13 ++
drivers/thunderbolt/tb.h | 2 +
include/linux/pci.h | 1 +
include/linux/pm_runtime.h | 7 +
15 files changed, 500 insertions(+), 11 deletions(-)
create mode 100644 drivers/thunderbolt/power.c
create mode 100644 drivers/thunderbolt/power.h


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