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# USB Core configuration
config USB_DEBUG
bool "USB verbose debug messages"
depends on USB
Say Y here if you want the USB core & hub drivers to produce a bunch
of debug messages to the system log. Select this if you are having a
problem with USB support and want to see more of what is going on.
bool "USB announce new devices"
depends on USB
default N
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"
depends on USB
bool "USB device filesystem (DEPRECATED)"
depends on USB
If you say Y here (and to "/proc file system support" in the "File
systems" section, above), you will get a file /proc/bus/usb/devices
which lists the devices currently connected to your USB bus or
busses, and for every connected device a file named
"/proc/bus/usb/xxx/yyy", where xxx is the bus number and yyy the
device number; the latter files can be used by user space programs
to talk directly to the device. These files are "virtual", meaning
they are generated on the fly and not stored on the hard drive.
You may need to mount the usbfs file system to see the files, use
mount -t usbfs none /proc/bus/usb
For the format of the various /proc/bus/usb/ files, please read
Modern Linux systems do not use this.
Usbfs entries are files and not character devices; usbfs can't
handle Access Control Lists (ACL) which are the default way to
grant access to USB devices for untrusted users of a desktop
The usbfs functionality is replaced by real device-nodes managed by
udev. These nodes lived in /dev/bus/usb and are used by libusb.
bool "USB device class-devices (DEPRECATED)"
depends on USB
default y
Userspace access to USB devices is granted by device-nodes exported
directly from the usbdev in sysfs. Old versions of the driver
core and udev needed additional class devices to export device nodes.
These additional devices are difficult to handle in userspace, if
information about USB interfaces must be available. One device
contains the device node, the other device contains the interface
data. Both devices are at the same level in sysfs (siblings) and one
can't access the other. The device node created directly by the
usb device is the parent device of the interface and therefore
easily accessible from the interface event.
This option provides backward compatibility for libusb device
nodes (lsusb) when usbfs is not used, and the following udev rule
doesn't exist:
SUBSYSTEM=="usb", ACTION=="add", ENV{DEVTYPE}=="usb_device", \
NAME="bus/usb/$env{BUSNUM}/$env{DEVNUM}", MODE="0644"
bool "Dynamic USB minor allocation"
depends on USB
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.
bool "USB runtime power management (suspend/resume and wakeup)"
depends on USB && PM_RUNTIME
If you say Y here, you can use driver calls or the sysfs
"power/level" file to suspend or resume individual USB
peripherals and to enable or disable autosuspend (see
Documentation/usb/power-management.txt for more details).
Also, USB "remote wakeup" signaling is supported, whereby some
USB devices (like keyboards and network adapters) can wake up
their parent hub. That wakeup cascades up the USB tree, and
could wake the system from states like suspend-to-RAM.
If you are unsure about this, say N here.
config USB_OTG
depends on USB && EXPERIMENTAL
depends on USB_SUSPEND
default n
bool "Rely on OTG Targeted Peripherals List"
depends on USB_OTG || EMBEDDED
default y if USB_OTG
default n if EMBEDDED
If you say Y here, the "otg_whitelist.h" file will be used as a
product whitelist, so USB peripherals not listed there will be
rejected during enumeration. This behavior is required by the
USB OTG 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.
Otherwise, peripherals not listed there will only generate a
warning and enumeration will continue. That's more like what
normal Linux-USB hosts do (other than the warning), and is
convenient for many stages of product development.
bool "Disable external hubs"
depends on USB_OTG || EMBEDDED
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.