Documentation/ABI/testing/sysfs-bus-thunderbolt

Source file repositories/reference/linux-study-clean/Documentation/ABI/testing/sysfs-bus-thunderbolt

File Facts

System
Linux kernel
Corpus path
Documentation/ABI/testing/sysfs-bus-thunderbolt
Extension
[no extension]
Size
14650 bytes
Lines
371
Domain
Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: Documentation
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

What:		/sys/bus/thunderbolt/devices/.../domainX/boot_acl
Date:		Jun 2018
KernelVersion:	4.17
Contact:	Mika Westerberg <mika.westerberg@linux.intel.com>
Description:	Holds a comma separated list of device unique_ids that
		are allowed to be connected automatically during system
		startup (e.g boot devices). The list always contains
		maximum supported number of unique_ids where unused
		entries are empty. This allows the userspace software
		to determine how many entries the controller supports.
		If there are multiple controllers, each controller has
		its own ACL list and size may be different between the
		controllers.

		System BIOS may have an option "Preboot ACL" or similar
		that needs to be selected before this list is taken into
		consideration.

		Software always updates a full list in each write.

		If a device is authorized automatically during boot its
		boot attribute is set to 1.

What:		/sys/bus/thunderbolt/devices/.../domainX/deauthorization
Date:		May 2021
KernelVersion:	5.12
Contact:	Mika Westerberg <mika.westerberg@linux.intel.com>
Description:	This attribute tells whether the system supports
		de-authorization of devices. Value of 1 means user can
		de-authorize PCIe tunnel by writing 0 to authorized
		attribute under each device.

What:		/sys/bus/thunderbolt/devices/.../domainX/iommu_dma_protection
Date:		Mar 2019
KernelVersion:	4.21
Contact:	Mika Westerberg <mika.westerberg@linux.intel.com>
Description:	This attribute tells whether the system uses IOMMU
		for DMA protection. Value of 1 means IOMMU is used 0 means
		it is not (DMA protection is solely based on Thunderbolt
		security levels).

What:		/sys/bus/thunderbolt/devices/.../domainX/security
Date:		Sep 2017
KernelVersion:	4.13
Contact:	Mika Westerberg <mika.westerberg@linux.intel.com>
Description:	This attribute holds current Thunderbolt security level
		set by the system BIOS. Possible values are:

		=======  ==================================================
		none     All devices are automatically authorized
		user     Devices are only authorized based on writing
		         appropriate value to the authorized attribute
		secure   Require devices that support secure connect at
			 minimum. User needs to authorize each device.
		dponly   Automatically tunnel Display port (and USB). No
			 PCIe tunnels are created.
		usbonly  Automatically tunnel USB controller of the
			 connected Thunderbolt dock (and Display Port). All
			 PCIe links downstream of the dock are removed.
		nopcie   USB4 system where PCIe tunneling is disabled from
			 the BIOS.
		=======  ==================================================

What:		/sys/bus/thunderbolt/devices/.../authorized
Date:		Sep 2017
KernelVersion:	4.13
Contact:	Mika Westerberg <mika.westerberg@linux.intel.com>
Description:	This attribute is used to authorize Thunderbolt devices
		after they have been connected. If the device is not
		authorized, no PCIe devices are available to the system.

Annotation

Implementation Notes