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Commit ce6a9002 authored by Mario Limonciello's avatar Mario Limonciello Committed by Andy Shevchenko
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platform/x86: Add driver to force WMI Thunderbolt controller power status 



Current implementations of Intel Thunderbolt controllers will go
into a low power mode when not in use.

Many machines containing these controllers also have a GPIO wired up
that can force the controller awake.  This is offered via a ACPI-WMI
interface intended to be manipulated by a userspace utility.

This mechanism is provided by Intel to OEMs to include in BIOS.
It uses an industry wide GUID that is populated in a separate _WDG
entry with no binary MOF.

This interface allows software such as fwupd to wake up thunderbolt
controllers to query the firmware version or flash new firmware.

Signed-off-by: default avatarMario Limonciello <mario.limonciello@dell.com>
Reviewed-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: default avatarYehezkel Bernat <yehezkel.bernat@intel.com>
Signed-off-by: default avatarDarren Hart (VMware) <dvhart@infradead.org>
[andy fixed merge conflicts and bump kernel version for ABI]
Signed-off-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
parent 2bd6bf03

Documentation/ABI/testing/sysfs-platform-intel-wmi-thunderbolt

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+11 −0
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What:		/sys/devices/platform/<platform>/force_power

Date:		September 2017

KernelVersion:	4.15

Contact:	"Mario Limonciello" <mario.limonciello@dell.com>

Description:

		Modify the platform force power state, influencing

		Thunderbolt controllers to turn on or off when no

		devices are connected (write-only)

		There are two available states:

		    * 0 -> Force power disabled

		    * 1 -> Force power enabled

Documentation/admin-guide/thunderbolt.rst

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@@ -197,3 +197,18 @@ information is missing. 


To recover from this mode, one needs to flash a valid NVM image to the

host host controller in the same way it is done in the previous chapter.



Forcing power

-------------

Many OEMs include a method that can be used to force the power of a

thunderbolt controller to an "On" state even if nothing is connected.

If supported by your machine this will be exposed by the WMI bus with

a sysfs attribute called "force_power".



For example the intel-wmi-thunderbolt driver exposes this attribute in:

  /sys/devices/platform/PNP0C14:00/wmi_bus/wmi_bus-PNP0C14:00/86CCFD48-205E-4A77-9C48-2021CBEDE341/force_power



  To force the power to on, write 1 to this attribute file.

  To disable force power, write 0 to this attribute file.



Note: it's currently not possible to query the force power state of a platform.

MAINTAINERS

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@@ -7092,6 +7092,11 @@ F: Documentation/wimax/README.i2400m 
F:	drivers/net/wimax/i2400m/

F:	include/uapi/linux/wimax/i2400m.h



INTEL WMI THUNDERBOLT FORCE POWER DRIVER

M:	Mario Limonciello <mario.limonciello@dell.com>

S:	Maintained

F:	drivers/platform/x86/intel-wmi-thunderbolt.c



INTEL(R) TRACE HUB

M:	Alexander Shishkin <alexander.shishkin@linux.intel.com>

S:	Supported

drivers/platform/x86/Kconfig

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@@ -658,6 +658,19 @@ config WMI_BMOF 
	  To compile this driver as a module, choose M here: the module will

	  be called wmi-bmof.



config INTEL_WMI_THUNDERBOLT

	tristate "Intel WMI thunderbolt force power driver"

	depends on ACPI_WMI

	default ACPI_WMI

	---help---

	  Say Y here if you want to be able to use the WMI interface on select

	  systems to force the power control of Intel Thunderbolt controllers.

	  This is useful for updating the firmware when devices are not plugged

	  into the controller.



	  To compile this driver as a module, choose M here: the module will

	  be called intel-wmi-thunderbolt.



config MSI_WMI

	tristate "MSI WMI extras"

	depends on ACPI_WMI

drivers/platform/x86/Makefile

+1 −0
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@@ -39,6 +39,7 @@ obj-$(CONFIG_PEAQ_WMI) += peaq-wmi.o 
obj-$(CONFIG_SURFACE3_WMI)	+= surface3-wmi.o

obj-$(CONFIG_TOPSTAR_LAPTOP)	+= topstar-laptop.o

obj-$(CONFIG_WMI_BMOF)		+= wmi-bmof.o

obj-$(CONFIG_INTEL_WMI_THUNDERBOLT)	+= intel-wmi-thunderbolt.o



# toshiba_acpi must link after wmi to ensure that wmi devices are found

# before toshiba_acpi initializes