What: /sys/bus/thunderbolt/devices/.../domainX/boot_acl
Date: Jun 2018
KernelVersion: 4.17
Contact: Mika Westerberg <[email protected]>
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 <[email protected]>
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 <[email protected]>
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 <[email protected]>
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 <[email protected]>
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.
Contents of this attribute will be 0 when the device is not
yet authorized.
Possible values are supported:
== ===================================================
0 The device will be de-authorized (only supported if
deauthorization attribute under domain contains 1)
1 The device will be authorized and connected
== ===================================================
When key attribute contains 32 byte hex string the possible
values are:
== ========================================================
0 The device will be de-authorized (only supported if
deauthorization attribute under domain contains 1)
1 The 32 byte hex string is added to the device NVM and
the device is authorized.
2 Send a challenge based on the 32 byte hex string. If the
challenge response from device is valid, the device is
authorized. In case of failure errno will be ENOKEY if
the device did not contain a key at all, and
EKEYREJECTED if the challenge response did not match.
== ========================================================
What: /sys/bus/thunderbolt/devices/.../boot
Date: Jun 2018
KernelVersion: 4.17
Contact: Mika Westerberg <[email protected]>
Description: This attribute contains 1 if Thunderbolt device was already
authorized on boot and 0 otherwise.
What: /sys/bus/thunderbolt/devices/.../generation
Date: Jan 2020
KernelVersion: 5.5
Contact: Christian Kellner <[email protected]>
Description: This attribute contains the generation of the Thunderbolt
controller associated with the device. It will contain 4
for USB4.
What: /sys/bus/thunderbolt/devices/.../key
Date: Sep 2017
KernelVersion: 4.13
Contact: Mika Westerberg <[email protected]>
Description: When a devices supports Thunderbolt secure connect it will
have this attribute. Writing 32 byte hex string changes
authorization to use the secure connection method instead.
Writing an empty string clears the key and regular connection
method can be used again.
What: /sys/bus/thunderbolt/devices/.../device
Date: Sep 2017
KernelVersion: 4.13
Contact: Mika Westerberg <[email protected]>
Description: This attribute contains id of this device extracted from
the device DROM.
What: /sys/bus/thunderbolt/devices/.../device_name
Date: Sep 2017
KernelVersion: 4.13
Contact: Mika Westerberg <[email protected]>
Description: This attribute contains name of this device extracted from
the device DROM.
What: /sys/bus/thunderbolt/devices/.../maxhopid
Date: Jul 2021
KernelVersion: 5.13
Contact: Mika Westerberg <[email protected]>
Description: Only set for XDomains. The maximum HopID the other host
supports as its input HopID.
What: /sys/bus/thunderbolt/devices/.../rx_speed
Date: Jan 2020
KernelVersion: 5.5
Contact: Mika Westerberg <[email protected]>
Description: This attribute reports the device RX speed per lane.
All RX lanes run at the same speed.
What: /sys/bus/thunderbolt/devices/.../rx_lanes
Date: Jan 2020
KernelVersion: 5.5
Contact: Mika Westerberg <[email protected]>
Description: This attribute reports number of RX lanes the device is
using simultaneously through its upstream port.
What: /sys/bus/thunderbolt/devices/.../tx_speed
Date: Jan 2020
KernelVersion: 5.5
Contact: Mika Westerberg <[email protected]>
Description: This attribute reports the TX speed per lane.
All TX lanes run at the same speed.
What: /sys/bus/thunderbolt/devices/.../tx_lanes
Date: Jan 2020
KernelVersion: 5.5
Contact: Mika Westerberg <[email protected]>
Description: This attribute reports number of TX lanes the device is
using simultaneously through its upstream port.
What: /sys/bus/thunderbolt/devices/.../vendor
Date: Sep 2017
KernelVersion: 4.13
Contact: Mika Westerberg <[email protected]>
Description: This attribute contains vendor id of this device extracted
from the device DROM.
What: /sys/bus/thunderbolt/devices/.../vendor_name
Date: Sep 2017
KernelVersion: 4.13
Contact: Mika Westerberg <[email protected]>
Description: This attribute contains vendor name of this device extracted
from the device DROM.
What: /sys/bus/thunderbolt/devices/.../unique_id
Date: Sep 2017
KernelVersion: 4.13
Contact: Mika Westerberg <[email protected]>
Description: This attribute contains unique_id string of this device.
This is either read from hardware registers (UUID on
newer hardware) or based on UID from the device DROM.
Can be used to uniquely identify particular device.
What: /sys/bus/thunderbolt/devices/.../nvm_version
Date: Sep 2017
KernelVersion: 4.13
Contact: Mika Westerberg <[email protected]>
Description: If the device has upgradeable firmware the version
number is available here. Format: %x.%x, major.minor.
If the device is in safe mode reading the file returns
-ENODATA instead as the NVM version is not available.
What: /sys/bus/thunderbolt/devices/.../nvm_authenticate
Date: Sep 2017
KernelVersion: 4.13
Contact: Mika Westerberg <[email protected]>
Description: When new NVM image is written to the non-active NVM
area (through non_activeX NVMem device), the
authentication procedure is started by writing to
this file.
If everything goes well, the device is
restarted with the new NVM firmware. If the image
verification fails an error code is returned instead.
This file will accept writing values "1", "2" or "3".
- Writing "1" will flush the image to the storage
area and authenticate the image in one action.
- Writing "2" will run some basic validation on the image
and flush it to the storage area.
- Writing "3" will authenticate the image that is
currently written in the storage area. This is only
supported with USB4 devices and retimers.
When read holds status of the last authentication
operation if an error occurred during the process. This
is directly the status value from the DMA configuration
based mailbox before the device is power cycled. Writing
0 here clears the status.
What: /sys/bus/thunderbolt/devices/.../nvm_authenticate_on_disconnect
Date: Oct 2020
KernelVersion: v5.9
Contact: Mario Limonciello <[email protected]>
Description: For supported devices, automatically authenticate the new Thunderbolt
image when the device is disconnected from the host system.
This file will accept writing values "1" or "2"
- Writing "1" will flush the image to the storage
area and prepare the device for authentication on disconnect.
- Writing "2" will run some basic validation on the image
and flush it to the storage area.
What: /sys/bus/thunderbolt/devices/<xdomain>.<service>/key
Date: Jan 2018
KernelVersion: 4.15
Contact: Mika Westerberg <[email protected]>
Description: This contains name of the property directory the XDomain
service exposes. This entry describes the protocol in
question. Following directories are already reserved by
the Apple XDomain specification:
======== ===============================================
network IP/ethernet over Thunderbolt
targetdm Target disk mode protocol over Thunderbolt
extdisp External display mode protocol over Thunderbolt
======== ===============================================
What: /sys/bus/thunderbolt/devices/<xdomain>.<service>/modalias
Date: Jan 2018
KernelVersion: 4.15
Contact: Mika Westerberg <[email protected]>
Description: Stores the same MODALIAS value emitted by uevent for
the XDomain service. Format: tbtsvc:kSpNvNrN
What: /sys/bus/thunderbolt/devices/<xdomain>.<service>/prtcid
Date: Jan 2018
KernelVersion: 4.15
Contact: Mika Westerberg <[email protected]>
Description: This contains XDomain protocol identifier the XDomain
service supports.
What: /sys/bus/thunderbolt/devices/<xdomain>.<service>/prtcvers
Date: Jan 2018
KernelVersion: 4.15
Contact: Mika Westerberg <[email protected]>
Description: This contains XDomain protocol version the XDomain
service supports.
What: /sys/bus/thunderbolt/devices/<xdomain>.<service>/prtcrevs
Date: Jan 2018
KernelVersion: 4.15
Contact: Mika Westerberg <[email protected]>
Description: This contains XDomain software version the XDomain
service supports.
What: /sys/bus/thunderbolt/devices/<xdomain>.<service>/prtcstns
Date: Jan 2018
KernelVersion: 4.15
Contact: Mika Westerberg <[email protected]>
Description: This contains XDomain service specific settings as
bitmask. Format: %x
What: /sys/bus/thunderbolt/devices/usb4_portX/connector
Date: April 2022
Contact: Heikki Krogerus <[email protected]>
Description:
Symlink to the USB Type-C connector. This link is only
created when USB Type-C Connector Class is enabled,
and only if the system firmware is capable of
describing the connection between a port and its
connector.
What: /sys/bus/thunderbolt/devices/usb4_portX/link
Date: Sep 2021
KernelVersion: v5.14
Contact: Mika Westerberg <[email protected]>
Description: Returns the current link mode. Possible values are
"usb4", "tbt" and "none".
What: /sys/bus/thunderbolt/devices/usb4_portX/offline
Date: Sep 2021
KernelVersion: v5.14
Contact: Rajmohan Mani <[email protected]>
Description: Writing 1 to this attribute puts the USB4 port into
offline mode. Only allowed when there is nothing
connected to the port (link attribute returns "none").
Once the port is in offline mode it does not receive any
hotplug events. This is used to update NVM firmware of
on-board retimers. Writing 0 puts the port back to
online mode.
This attribute is only visible if the platform supports
powering on retimers when there is no cable connected.
What: /sys/bus/thunderbolt/devices/usb4_portX/rescan
Date: Sep 2021
KernelVersion: v5.14
Contact: Rajmohan Mani <[email protected]>
Description: When the USB4 port is in offline mode writing 1 to this
attribute forces rescan of the sideband for on-board
retimers. Each retimer appear under the USB4 port as if
the USB4 link was up. These retimers act in the same way
as if the cable was connected so upgrading their NVM
firmware can be done the usual way.
What: /sys/bus/thunderbolt/devices/<device>:<port>.<index>/device
Date: Oct 2020
KernelVersion: v5.9
Contact: Mika Westerberg <[email protected]>
Description: Retimer device identifier read from the hardware.
What: /sys/bus/thunderbolt/devices/<device>:<port>.<index>/nvm_authenticate
Date: Oct 2020
KernelVersion: v5.9
Contact: Mika Westerberg <[email protected]>
Description: When new NVM image is written to the non-active NVM
area (through non_activeX NVMem device), the
authentication procedure is started by writing 1 to
this file. If everything goes well, the device is
restarted with the new NVM firmware. If the image
verification fails an error code is returned instead.
When read holds status of the last authentication
operation if an error occurred during the process.
Format: %x.
What: /sys/bus/thunderbolt/devices/<device>:<port>.<index>/nvm_version
Date: Oct 2020
KernelVersion: v5.9
Contact: Mika Westerberg <[email protected]>
Description: Holds retimer NVM version number. Format: %x.%x, major.minor.
What: /sys/bus/thunderbolt/devices/<device>:<port>.<index>/vendor
Date: Oct 2020
KernelVersion: v5.9
Contact: Mika Westerberg <[email protected]>
Description: Retimer vendor identifier read from the hardware.
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