| 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. |
| |
| Certified Wireless USB devices are not authorized |
| initially and should be (by writing 1) after the |
| device has been authenticated. |
| |
| What: /sys/bus/usb/device/.../wusb_cdid |
| Date: July 2008 |
| KernelVersion: 2.6.27 |
| Contact: David Vrabel <david.vrabel@csr.com> |
| Description: |
| For Certified Wireless USB devices only. |
| |
| A devices's CDID, as 16 space-separated hex octets. |
| |
| What: /sys/bus/usb/device/.../wusb_ck |
| Date: July 2008 |
| KernelVersion: 2.6.27 |
| Contact: David Vrabel <david.vrabel@csr.com> |
| Description: |
| For Certified Wireless USB devices only. |
| |
| Write the device's connection key (CK) to start the |
| authentication of the device. The CK is 16 |
| space-separated hex octets. |
| |
| What: /sys/bus/usb/device/.../wusb_disconnect |
| Date: July 2008 |
| KernelVersion: 2.6.27 |
| Contact: David Vrabel <david.vrabel@csr.com> |
| Description: |
| For Certified Wireless USB devices only. |
| |
| Write a 1 to force the device to disconnect |
| (equivalent to unplugging a wired USB device). |
| |
| 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/.../removable |
| Date: February 2012 |
| Contact: Matthew Garrett <mjg@redhat.com> |
| Description: |
| Some information about whether a given USB device is |
| physically fixed to the platform can be inferred from a |
| combination of hub descriptor bits and platform-specific data |
| such as ACPI. This file will read either "removable" or |
| "fixed" if the information is available, and "unknown" |
| otherwise. |
| |
| 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/.../(hub interface)/portX |
| Date: August 2012 |
| Contact: Lan Tianyu <tianyu.lan@intel.com> |
| Description: |
| The /sys/bus/usb/devices/.../(hub interface)/portX |
| is usb port device's sysfs directory. |
| |
| What: /sys/bus/usb/devices/.../(hub interface)/portX/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", "wired" and "not used" if the |
| information is available, and "unknown" otherwise. |
| |
| What: /sys/bus/usb/devices/.../(hub interface)/portX/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)/portX/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. |
| |
| What: /sys/bus/usb/devices/.../(hub interface)/portX/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/.../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) |