xref: /drivers/usb/core/Kconfig

#
# USB Core configuration
#
config USB_DEBUG
	bool "USB verbose debug messages"
	depends on USB
	help
	  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.

config USB_ANNOUNCE_NEW_DEVICES
	bool "USB announce new devices"
	depends on USB
	default N
	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"
	depends on USB

config USB_DEVICEFS
	bool "USB device filesystem (DEPRECATED)"
	depends on USB
	---help---
	  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
	  <file:Documentation/usb/proc_usb_info.txt>.

	  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
	  system.

	  The usbfs functionality is replaced by real device-nodes managed by
	  udev.  These nodes lived in /dev/bus/usb and are used by libusb.

config USB_DEVICE_CLASS
	bool "USB device class-devices (DEPRECATED)"
	depends on USB
	default y
	---help---
	  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"

config USB_DYNAMIC_MINORS
	bool "Dynamic USB minor allocation"
	depends on USB
	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_SUSPEND
	bool "USB runtime power management (autosuspend) and wakeup"
	depends on USB && PM_RUNTIME
	help
	  If you say Y here, you can use driver calls or the sysfs
	  "power/control" file to enable or disable autosuspend for
	  individual USB peripherals (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
	bool "OTG support"
	depends on USB && EXPERIMENTAL
	depends on USB_SUSPEND
	default n
	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_WHITELIST
	bool "Rely on OTG Targeted Peripherals List"
	depends on USB_OTG || EXPERT
	default y if USB_OTG
	default n if EXPERT
	help
	  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.

config USB_OTG_BLACKLIST_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.