# SPDX-License-Identifier: GPL-2.0 # # USB Core configuration # config USB_ANNOUNCE_NEW_DEVICES bool "USB announce new devices" help Say Y here if you want the USB core to always announce the idVendor, idProduct, Manufacturer, Product, and SerialNumber strings for every new USB device to the syslog. This option is usually used by distro vendors to help with debugging and to let users know what specific device was added to the machine in what location. If you do not want this kind of information sent to the system log, or have any doubts about this, say N here. comment "Miscellaneous USB options" config USB_DEFAULT_PERSIST bool "Enable USB persist by default" default y help Say N here if you don't want USB power session persistence enabled by default. If you say N it will make suspended USB devices that lose power get reenumerated as if they had been unplugged, causing any mounted filesystems to be lost. The persist feature can still be enabled for individual devices through the power/persist sysfs node. See Documentation/driver-api/usb/persist.rst for more info. If you have any questions about this, say Y here, only say N if you know exactly what you are doing. config USB_FEW_INIT_RETRIES bool "Limit USB device initialization to only a few retries" help When a new USB device is detected, the kernel tries very hard to initialize and enumerate it, with lots of nested retry loops. This almost always works, but when it fails it can take a long time. This option tells the kernel to make only a few retry attempts, so that the total time required for a failed initialization is no more than 30 seconds (as required by the USB OTG spec). Say N here unless you require new-device enumeration failure to occur within 30 seconds (as might be needed in an embedded application). config USB_DYNAMIC_MINORS bool "Dynamic USB minor allocation" help If you say Y here, the USB subsystem will use dynamic minor allocation for any device that uses the USB major number. This means that you can have more than 16 of a single type of device (like USB printers). If you are unsure about this, say N here. config USB_OTG bool "OTG support" depends on PM help The most notable feature of USB OTG is support for a "Dual-Role" device, which can act as either a device or a host. The initial role is decided by the type of plug inserted and can be changed later when two dual role devices talk to each other. Select this only if your board has Mini-AB/Micro-AB connector. config USB_OTG_PRODUCTLIST bool "Rely on OTG and EH Targeted Peripherals List" depends on USB help If you say Y here, the "otg_productlist.h" file will be used as a product list, so USB peripherals not listed there will be rejected during enumeration. This behavior is required by the USB OTG and EH specification for all devices not on your product's "Targeted Peripherals List". "Embedded Hosts" are likewise allowed to support only a limited number of peripherals. config USB_OTG_DISABLE_EXTERNAL_HUB bool "Disable external hubs" depends on USB_OTG || EXPERT help If you say Y here, then Linux will refuse to enumerate external hubs. OTG hosts are allowed to reduce hardware and software costs by not supporting external hubs. So are "Embedded Hosts" that don't offer OTG support. config USB_OTG_FSM tristate "USB 2.0 OTG FSM implementation" depends on USB && USB_OTG select USB_PHY help Implements OTG Finite State Machine as specified in On-The-Go and Embedded Host Supplement to the USB Revision 2.0 Specification. config USB_LEDS_TRIGGER_USBPORT tristate "USB port LED trigger" depends on USB && LEDS_TRIGGERS help This driver allows LEDs to be controlled by USB events. Enabling this trigger allows specifying list of USB ports that should turn on LED when some USB device gets connected. config USB_AUTOSUSPEND_DELAY int "Default autosuspend delay" depends on USB default 2 help The default autosuspend delay in seconds. Can be overridden with the usbcore.autosuspend command line or module parameter. The default value Linux has always had is 2 seconds. Change this value if you want a different delay and cannot modify the command line or module parameter.