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# SPDX-License-Identifier: GPL-2.0
# USB Core configuration
bool "USB announce new devices"
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"
bool "Enable USB persist by default"
default y
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.
bool "Limit USB device initialization to only a few retries"
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
bool "Dynamic USB minor allocation"
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
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
bool "Rely on OTG and EH Targeted Peripherals List"
depends on USB
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.
bool "Disable external hubs"
depends on USB_OTG || EXPERT
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
Implements OTG Finite State Machine as specified in On-The-Go
and Embedded Host Supplement to the USB Revision 2.0 Specification.
tristate "USB port LED trigger"
depends on USB && LEDS_TRIGGERS
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.
int "Default autosuspend delay"
depends on USB
default 2
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.