diff options
Diffstat (limited to 'Documentation/ABI/testing/sysfs-bus-usb')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-usb | 59 |
1 files changed, 58 insertions, 1 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb index c702c78f24d8..559baa5c418c 100644 --- a/Documentation/ABI/testing/sysfs-bus-usb +++ b/Documentation/ABI/testing/sysfs-bus-usb @@ -189,6 +189,38 @@ Description: 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/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)/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> @@ -197,7 +229,14 @@ Description: 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. + 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)/portX + OVER_CURRENT_COUNT=[current value of this sysfs attribute] What: /sys/bus/usb/devices/.../(hub interface)/portX/usb3_lpm_permit Date: November 2015 @@ -236,3 +275,21 @@ Description: 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) |