| What: /sys/bus/usb/devices/<INTERFACE>/authorized |
| Date: August 2015 |
| Description: |
| This allows to authorize (1) or deauthorize (0) |
| individual interfaces instead a whole device |
| in contrast to the device authorization. |
| If a deauthorized interface will be authorized |
| so the driver probing must be triggered manually |
| by writing INTERFACE to /sys/bus/usb/drivers_probe |
| This allows to avoid side-effects with drivers |
| that need multiple interfaces. |
| |
| A deauthorized interface cannot be probed or claimed. |
| |
| What: /sys/bus/usb/devices/usbX/interface_authorized_default |
| Date: August 2015 |
| Description: |
| This is used as value that determines if interfaces |
| would be authorized by default. |
| The value can be 1 or 0. It's by default 1. |
| |
| What: /sys/bus/usb/device/.../authorized |
| Date: July 2008 |
| KernelVersion: 2.6.26 |
| Contact: David Vrabel <david.vrabel@csr.com> |
| Description: |
| Authorized devices are available for use by device |
| drivers, non-authorized one are not. By default, wired |
| USB devices are authorized. |
| |
| What: /sys/bus/usb/drivers/.../new_id |
| Date: October 2011 |
| Contact: linux-usb@vger.kernel.org |
| Description: |
| Writing a device ID to this file will attempt to |
| dynamically add a new device ID to a USB device driver. |
| This may allow the driver to support more hardware than |
| was included in the driver's static device ID support |
| table at compile time. The format for the device ID is: |
| idVendor idProduct bInterfaceClass RefIdVendor RefIdProduct |
| The vendor ID and device ID fields are required, the |
| rest is optional. The `Ref*` tuple can be used to tell the |
| driver to use the same driver_data for the new device as |
| it is used for the reference device. |
| Upon successfully adding an ID, the driver will probe |
| for the device and attempt to bind to it. For example:: |
| |
| # echo "8086 10f5" > /sys/bus/usb/drivers/foo/new_id |
| |
| Here add a new device (0458:7045) using driver_data from |
| an already supported device (0458:704c):: |
| |
| # echo "0458 7045 0 0458 704c" > /sys/bus/usb/drivers/foo/new_id |
| |
| Reading from this file will list all dynamically added |
| device IDs in the same format, with one entry per |
| line. For example:: |
| |
| # cat /sys/bus/usb/drivers/foo/new_id |
| 8086 10f5 |
| dead beef 06 |
| f00d cafe |
| |
| The list will be truncated at PAGE_SIZE bytes due to |
| sysfs restrictions. |
| |
| What: /sys/bus/usb-serial/drivers/.../new_id |
| Date: October 2011 |
| Contact: linux-usb@vger.kernel.org |
| Description: |
| For serial USB drivers, this attribute appears under the |
| extra bus folder "usb-serial" in sysfs; apart from that |
| difference, all descriptions from the entry |
| "/sys/bus/usb/drivers/.../new_id" apply. |
| |
| What: /sys/bus/usb/drivers/.../remove_id |
| Date: November 2009 |
| Contact: CHENG Renquan <rqcheng@smu.edu.sg> |
| Description: |
| Writing a device ID to this file will remove an ID |
| that was dynamically added via the new_id sysfs entry. |
| The format for the device ID is: |
| idVendor idProduct. After successfully |
| removing an ID, the driver will no longer support the |
| device. This is useful to ensure auto probing won't |
| match the driver to the device. For example: |
| # echo "046d c315" > /sys/bus/usb/drivers/foo/remove_id |
| |
| Reading from this file will list the dynamically added |
| device IDs, exactly like reading from the entry |
| "/sys/bus/usb/drivers/.../new_id" |
| |
| What: /sys/bus/usb/devices/.../power/usb2_hardware_lpm |
| Date: September 2011 |
| Contact: Andiry Xu <andiry.xu@amd.com> |
| Description: |
| If CONFIG_PM is set and a USB 2.0 lpm-capable device is plugged |
| in to a xHCI host which support link PM, it will perform a LPM |
| test; if the test is passed and host supports USB2 hardware LPM |
| (xHCI 1.0 feature), USB2 hardware LPM will be enabled for the |
| device and the USB device directory will contain a file named |
| power/usb2_hardware_lpm. The file holds a string value (enable |
| or disable) indicating whether or not USB2 hardware LPM is |
| enabled for the device. Developer can write y/Y/1 or n/N/0 to |
| the file to enable/disable the feature. |
| |
| What: /sys/bus/usb/devices/.../power/usb3_hardware_lpm_u1 |
| /sys/bus/usb/devices/.../power/usb3_hardware_lpm_u2 |
| Date: November 2015 |
| Contact: Kevin Strasser <kevin.strasser@linux.intel.com> |
| Lu Baolu <baolu.lu@linux.intel.com> |
| Description: |
| If CONFIG_PM is set and a USB 3.0 lpm-capable device is plugged |
| in to a xHCI host which supports link PM, it will check if U1 |
| and U2 exit latencies have been set in the BOS descriptor; if |
| the check is passed and the host supports USB3 hardware LPM, |
| USB3 hardware LPM will be enabled for the device and the USB |
| device directory will contain two files named |
| power/usb3_hardware_lpm_u1 and power/usb3_hardware_lpm_u2. These |
| files hold a string value (enable or disable) indicating whether |
| or not USB3 hardware LPM U1 or U2 is enabled for the device. |
| |
| What: /sys/bus/usb/devices/.../ltm_capable |
| Date: July 2012 |
| Contact: Sarah Sharp <sarah.a.sharp@linux.intel.com> |
| Description: |
| USB 3.0 devices may optionally support Latency Tolerance |
| Messaging (LTM). They indicate their support by setting a bit |
| in the bmAttributes field of their SuperSpeed BOS descriptors. |
| If that bit is set for the device, ltm_capable will read "yes". |
| If the device doesn't support LTM, the file will read "no". |
| The file will be present for all speeds of USB devices, and will |
| always read "no" for USB 1.1 and USB 2.0 devices. |
| |
| What: /sys/bus/usb/devices/<INTERFACE>/wireless_status |
| Date: February 2023 |
| Contact: Bastien Nocera <hadess@hadess.net> |
| Description: |
| Some USB devices use a USB receiver dongle to communicate |
| wirelessly with their device using proprietary protocols. This |
| attribute allows user-space to know whether the device is |
| connected to its receiver dongle, and, for example, consider |
| the device to be absent when choosing whether to show the |
| device's battery, show a headset in a list of outputs, or show |
| an on-screen keyboard if the only wireless keyboard is |
| turned off. |
| This attribute is not to be used to replace protocol specific |
| statuses available in WWAN, WLAN/Wi-Fi, Bluetooth, etc. |
| If the device does not use a receiver dongle with a wireless |
| device, then this attribute will not exist. |
| |
| What: /sys/bus/usb/devices/.../<hub_interface>/port<X> |
| Date: August 2012 |
| Contact: Lan Tianyu <tianyu.lan@intel.com> |
| Description: |
| The /sys/bus/usb/devices/.../<hub_interface>/port<X> |
| is usb port device's sysfs directory. |
| |
| What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/connect_type |
| Date: January 2013 |
| Contact: Lan Tianyu <tianyu.lan@intel.com> |
| Description: |
| Some platforms provide usb port connect types through ACPI. |
| This attribute is to expose these information to user space. |
| The file will read "hotplug", "hardwired" and "not used" if the |
| information is available, and "unknown" otherwise. |
| |
| What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/location |
| Date: October 2018 |
| Contact: Bjørn Mork <bjorn@mork.no> |
| Description: |
| Some platforms provide usb port physical location through |
| firmware. This is used by the kernel to pair up logical ports |
| mapping to the same physical connector. The attribute exposes the |
| raw location value as a hex integer. |
| |
| |
| What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/quirks |
| Date: May 2018 |
| Contact: Nicolas Boichat <drinkcat@chromium.org> |
| Description: |
| In some cases, we care about time-to-active for devices |
| connected on a specific port (e.g. non-standard USB port like |
| pogo pins), where the device to be connected is known in |
| advance, and behaves well according to the specification. |
| This attribute is a bit-field that controls the behavior of |
| a specific port: |
| |
| - Bit 0 of this field selects the "old" enumeration scheme, |
| as it is considerably faster (it only causes one USB reset |
| instead of 2). |
| |
| The old enumeration scheme can also be selected globally |
| using /sys/module/usbcore/parameters/old_scheme_first, but |
| it is often not desirable as the new scheme was introduced to |
| increase compatibility with more devices. |
| - Bit 1 reduces TRSTRCY to the 10 ms that are required by the |
| USB 2.0 specification, instead of the 50 ms that are normally |
| used to help make enumeration work better on some high speed |
| devices. |
| |
| What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/over_current_count |
| Date: February 2018 |
| Contact: Richard Leitner <richard.leitner@skidata.com> |
| Description: |
| Most hubs are able to detect over-current situations on their |
| ports and report them to the kernel. This attribute is to expose |
| the number of over-current situation occurred on a specific port |
| to user space. This file will contain an unsigned 32 bit value |
| which wraps to 0 after its maximum is reached. This file supports |
| poll() for monitoring changes to this value in user space. |
| |
| Any time this value changes the corresponding hub device will send a |
| udev event with the following attributes:: |
| |
| OVER_CURRENT_PORT=/sys/bus/usb/devices/.../<hub_interface>/port<X> |
| OVER_CURRENT_COUNT=[current value of this sysfs attribute] |
| |
| What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/usb3_lpm_permit |
| Date: November 2015 |
| Contact: Lu Baolu <baolu.lu@linux.intel.com> |
| Description: |
| Some USB3.0 devices are not friendly to USB3 LPM. usb3_lpm_permit |
| attribute allows enabling/disabling usb3 lpm of a port. It takes |
| effect both before and after a usb device is enumerated. Supported |
| values are "0" if both u1 and u2 are NOT permitted, "u1" if only u1 |
| is permitted, "u2" if only u2 is permitted, "u1_u2" if both u1 and |
| u2 are permitted. |
| |
| What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/connector |
| Date: December 2021 |
| Contact: Heikki Krogerus <heikki.krogerus@linux.intel.com> |
| Description: |
| Link to the USB Type-C connector when available. 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/usb/devices/.../<hub_interface>/port<X>/disable |
| Date: June 2022 |
| Contact: Michael Grzeschik <m.grzeschik@pengutronix.de> |
| Description: |
| This file controls the state of a USB port, including |
| Vbus power output (but only on hubs that support |
| power switching -- most hubs don't support it). If |
| a port is disabled, the port is unusable: Devices |
| attached to the port will not be detected, initialized, |
| or enumerated. |
| |
| What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/early_stop |
| Date: Sep 2022 |
| Contact: Ray Chi <raychi@google.com> |
| Description: |
| Some USB hosts have some watchdog mechanisms so that the device |
| may enter ramdump if it takes a long time during port initialization. |
| This attribute allows each port just has two attempts so that the |
| port initialization will be failed quickly. In addition, if a port |
| which is marked with early_stop has failed to initialize, it will ignore |
| all future connections until this attribute is clear. |
| |
| What: /sys/bus/usb/devices/.../<hub_interface>/port<X>/state |
| Date: June 2023 |
| Contact: Roy Luo <royluo@google.com> |
| Description: |
| Indicates current state of the USB device attached to the port. |
| Valid states are: 'not-attached', 'attached', 'powered', |
| 'reconnecting', 'unauthenticated', 'default', 'addressed', |
| 'configured', and 'suspended'. This file supports poll() to |
| monitor the state change from user space. |
| |
| What: /sys/bus/usb/devices/.../power/usb2_lpm_l1_timeout |
| Date: May 2013 |
| Contact: Mathias Nyman <mathias.nyman@linux.intel.com> |
| Description: |
| USB 2.0 devices may support hardware link power management (LPM) |
| L1 sleep state. The usb2_lpm_l1_timeout attribute allows |
| tuning the timeout for L1 inactivity timer (LPM timer), e.g. |
| needed inactivity time before host requests the device to go to L1 sleep. |
| Useful for power management tuning. |
| Supported values are 0 - 65535 microseconds. |
| |
| What: /sys/bus/usb/devices/.../power/usb2_lpm_besl |
| Date: May 2013 |
| Contact: Mathias Nyman <mathias.nyman@linux.intel.com> |
| Description: |
| USB 2.0 devices that support hardware link power management (LPM) |
| L1 sleep state now use a best effort service latency value (BESL) to |
| indicate the best effort to resumption of service to the device after the |
| initiation of the resume event. |
| If the device does not have a preferred besl value then the host can select |
| one instead. This usb2_lpm_besl attribute allows to tune the host selected besl |
| value in order to tune power saving and service latency. |
| |
| Supported values are 0 - 15. |
| More information on how besl values map to microseconds can be found in |
| USB 2.0 ECN Errata for Link Power Management, section 4.10) |
| |
| What: /sys/bus/usb/devices/.../rx_lanes |
| Date: March 2018 |
| Contact: Mathias Nyman <mathias.nyman@linux.intel.com> |
| Description: |
| Number of rx lanes the device is using. |
| USB 3.2 adds Dual-lane support, 2 rx and 2 tx lanes over Type-C. |
| Inter-Chip SSIC devices support asymmetric lanes up to 4 lanes per |
| direction. Devices before USB 3.2 are single lane (rx_lanes = 1) |
| |
| What: /sys/bus/usb/devices/.../tx_lanes |
| Date: March 2018 |
| Contact: Mathias Nyman <mathias.nyman@linux.intel.com> |
| Description: |
| Number of tx lanes the device is using. |
| USB 3.2 adds Dual-lane support, 2 rx and 2 tx -lanes over Type-C. |
| Inter-Chip SSIC devices support asymmetric lanes up to 4 lanes per |
| direction. Devices before USB 3.2 are single lane (tx_lanes = 1) |
| |
| What: /sys/bus/usb/devices/.../typec |
| Date: November 2023 |
| Contact: Heikki Krogerus <heikki.krogerus@linux.intel.com> |
| Description: |
| Symlink to the USB Type-C partner device. USB Type-C partner |
| represents the component that communicates over the |
| Configuration Channel (CC signal on USB Type-C connectors and |
| cables) with the local port. |
| |
| What: /sys/bus/usb/devices/usbX/bAlternateSetting |
| Description: |
| The current interface alternate setting number, in decimal. |
| |
| See USB specs for its meaning. |
| |
| What: /sys/bus/usb/devices/usbX/bcdDevice |
| Description: |
| The device's release number, in hexadecimal. |
| |
| See USB specs for its meaning. |
| |
| What: /sys/bus/usb/devices/usbX/bConfigurationValue |
| Description: |
| While a USB device typically have just one configuration |
| setting, some devices support multiple configurations. |
| |
| This value shows the current configuration, in decimal. |
| |
| Changing its value will change the device's configuration |
| to another setting. |
| |
| The number of configurations supported by a device is at: |
| |
| /sys/bus/usb/devices/usbX/bNumConfigurations |
| |
| See USB specs for its meaning. |
| |
| What: /sys/bus/usb/devices/usbX/bDeviceClass |
| Description: |
| Class code of the device, in hexadecimal. |
| |
| See USB specs for its meaning. |
| |
| What: /sys/bus/usb/devices/usbX/bDeviceProtocol |
| Description: |
| Protocol code of the device, in hexadecimal. |
| |
| See USB specs for its meaning. |
| |
| What: /sys/bus/usb/devices/usbX/bDeviceSubClass |
| Description: |
| Subclass code of the device, in hexadecimal. |
| |
| See USB specs for its meaning. |
| |
| What: /sys/bus/usb/devices/usbX/bInterfaceClass |
| Description: |
| Class code of the interface, in hexadecimal. |
| |
| See USB specs for its meaning. |
| |
| What: /sys/bus/usb/devices/usbX/bInterfaceNumber |
| Description: |
| Interface number, in hexadecimal. |
| |
| See USB specs for its meaning. |
| |
| What: /sys/bus/usb/devices/usbX/bInterfaceProtocol |
| Description: |
| Protocol code of the interface, in hexadecimal. |
| |
| See USB specs for its meaning. |
| |
| What: /sys/bus/usb/devices/usbX/bInterfaceSubClass |
| Description: |
| Subclass code of the interface, in hexadecimal. |
| |
| See USB specs for its meaning. |
| |
| What: /sys/bus/usb/devices/usbX/bmAttributes |
| Description: |
| Attributes of the current configuration, in hexadecimal. |
| |
| See USB specs for its meaning. |
| |
| What: /sys/bus/usb/devices/usbX/bMaxPacketSize0 |
| Description: |
| Maximum endpoint 0 packet size, in decimal. |
| |
| See USB specs for its meaning. |
| |
| What: /sys/bus/usb/devices/usbX/bMaxPower |
| Description: |
| Maximum power consumption of the active configuration of |
| the device, in miliamperes. |
| |
| What: /sys/bus/usb/devices/usbX/bNumConfigurations |
| Description: |
| Number of the possible configurations of the device, in |
| decimal. The current configuration is controlled via: |
| |
| /sys/bus/usb/devices/usbX/bConfigurationValue |
| |
| See USB specs for its meaning. |
| |
| What: /sys/bus/usb/devices/usbX/bNumEndpoints |
| Description: |
| Number of endpoints used on this interface, in hexadecimal. |
| |
| See USB specs for its meaning. |
| |
| What: /sys/bus/usb/devices/usbX/bNumInterfaces |
| Description: |
| Number of interfaces on this device, in decimal. |
| |
| What: /sys/bus/usb/devices/usbX/busnum |
| Description: |
| Number of the bus. |
| |
| What: /sys/bus/usb/devices/usbX/configuration |
| Description: |
| Contents of the string descriptor associated with the |
| current configuration. It may include the firmware version |
| of a device and/or its serial number. |
| |
| What: /sys/bus/usb/devices/usbX/descriptors |
| Description: |
| Contains the interface descriptors, in binary. |
| |
| What: /sys/bus/usb/devices/usbX/bos_descriptors |
| Date: March 2024 |
| Contact: Elbert Mai <code@elbertmai.com> |
| Description: |
| Binary file containing the cached binary device object store (BOS) |
| of the device. This consists of the BOS descriptor followed by the |
| set of device capability descriptors. All descriptors read from |
| this file are in bus-endian format. Note that the kernel will not |
| request the BOS from a device if its bcdUSB is less than 0x0201. |
| |
| What: /sys/bus/usb/devices/usbX/idProduct |
| Description: |
| Product ID, in hexadecimal. |
| |
| What: /sys/bus/usb/devices/usbX/idVendor |
| Description: |
| Vendor ID, in hexadecimal. |
| |
| What: /sys/bus/usb/devices/usbX/devspec |
| Description: |
| Displays the Device Tree Open Firmware node of the interface. |
| |
| What: /sys/bus/usb/devices/usbX/avoid_reset_quirk |
| Description: |
| Most devices have this set to zero. |
| |
| If the value is 1, enable a USB quirk that prevents this |
| device to use reset. |
| |
| (read/write) |
| |
| What: /sys/bus/usb/devices/usbX/devnum |
| Description: |
| USB interface device number, in decimal. |
| |
| What: /sys/bus/usb/devices/usbX/devpath |
| Description: |
| String containing the USB interface device path. |
| |
| What: /sys/bus/usb/devices/usbX/manufacturer |
| Description: |
| Vendor specific string containing the name of the |
| manufacturer of the device. |
| |
| What: /sys/bus/usb/devices/usbX/maxchild |
| Description: |
| Number of ports of an USB hub |
| |
| What: /sys/bus/usb/devices/usbX/persist |
| Description: |
| Keeps the device even if it gets disconnected. |
| |
| What: /sys/bus/usb/devices/usbX/product |
| Description: |
| Vendor specific string containing the name of the |
| device's product. |
| |
| What: /sys/bus/usb/devices/usbX/speed |
| Description: |
| Shows the device's max speed, according to the USB version, |
| in Mbps. |
| Can be: |
| |
| ======= ==================== |
| Unknown speed unknown |
| 1.5 Low speed |
| 15 Full speed |
| 480 High Speed |
| 5000 Super Speed |
| 10000 Super Speed+ |
| 20000 Super Speed+ Gen 2x2 |
| ======= ==================== |
| |
| What: /sys/bus/usb/devices/usbX/supports_autosuspend |
| Description: |
| Returns 1 if the device doesn't support autosuspend. |
| Otherwise, returns 0. |
| |
| What: /sys/bus/usb/devices/usbX/urbnum |
| Description: |
| Number of URBs submitted for the whole device. |
| |
| What: /sys/bus/usb/devices/usbX/version |
| Description: |
| String containing the USB device version, as encoded |
| at the BCD descriptor. |
| |
| What: /sys/bus/usb/devices/usbX/power/autosuspend |
| Description: |
| Time in milliseconds for the device to autosuspend. If the |
| value is negative, then autosuspend is prevented. |
| |
| (read/write) |
| |
| What: /sys/bus/usb/devices/usbX/power/active_duration |
| Description: |
| The total time the device has not been suspended. |
| |
| What: /sys/bus/usb/devices/usbX/power/connected_duration |
| Description: |
| The total time (in msec) that the device has been connected. |
| |
| What: /sys/bus/usb/devices/usbX/power/level |
| Description: |
| |
| What: /sys/bus/usb/devices/usbX/ep_<N>/bEndpointAddress |
| Description: |
| The address of the endpoint described by this descriptor, |
| in hexadecimal. The endpoint direction on this bitmapped field |
| is also shown at: |
| |
| /sys/bus/usb/devices/usbX/ep_<N>/direction |
| |
| See USB specs for its meaning. |
| |
| What: /sys/bus/usb/devices/usbX/ep_<N>/bInterval |
| Description: |
| The interval of the endpoint as described on its descriptor, |
| in hexadecimal. The actual interval depends on the version |
| of the USB. Also shown in time units at |
| /sys/bus/usb/devices/usbX/ep_<N>/interval. |
| |
| What: /sys/bus/usb/devices/usbX/ep_<N>/bLength |
| Description: |
| Number of bytes of the endpoint descriptor, in hexadecimal. |
| |
| What: /sys/bus/usb/devices/usbX/ep_<N>/bmAttributes |
| Description: |
| Attributes which apply to the endpoint as described on its |
| descriptor, in hexadecimal. The endpoint type on this |
| bitmapped field is also shown at: |
| |
| /sys/bus/usb/devices/usbX/ep_<N>/type |
| |
| See USB specs for its meaning. |
| |
| What: /sys/bus/usb/devices/usbX/ep_<N>/direction |
| Description: |
| Direction of the endpoint. Can be: |
| |
| - both (on control endpoints) |
| - in |
| - out |
| |
| What: /sys/bus/usb/devices/usbX/ep_<N>/interval |
| Description: |
| Interval for polling endpoint for data transfers, in |
| milisseconds or microseconds. |
| |
| What: /sys/bus/usb/devices/usbX/ep_<N>/type |
| Description: |
| Descriptor type. Can be: |
| |
| - Control |
| - Isoc |
| - Bulk |
| - Interrupt |
| - unknown |
| |
| What: /sys/bus/usb/devices/usbX/ep_<N>/wMaxPacketSize |
| Description: |
| Maximum packet size this endpoint is capable of |
| sending or receiving, in hexadecimal. |
