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# USB Core configuration
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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.
comment "Miscellaneous USB options"
depends on USB
config USB_DEVICEFS
bool "USB device filesystem"
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>.
Usbfs files 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 live 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 (EXPERIMENTAL)"
depends on USB && EXPERIMENTAL
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 selective suspend/resume and wakeup (EXPERIMENTAL)"
depends on USB && PM && EXPERIMENTAL
help
If you say Y here, you can use driver calls or the sysfs
"power/state" file to suspend or resume individual USB
peripherals.
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_PERSIST
bool "USB device persistence during system suspend (DANGEROUS)"
depends on USB && PM && EXPERIMENTAL
default n
help
If you say Y here and enable the "power/persist" attribute
for a USB device, the device's data structures will remain
persistent across system suspend, even if the USB bus loses
power. (This includes hibernation, also known as swsusp or
suspend-to-disk.) The devices will reappear as if by magic
when the system wakes up, with no need to unmount USB
filesystems, rmmod host-controller drivers, or do anything
else.
WARNING: This option can be dangerous!
If a USB device is replaced by another of the same type while
the system is asleep, there's a good chance the kernel won't
detect the change. Likewise if the media in a USB storage
device is replaced. When this happens it's almost certain to
cause data corruption and maybe even crash your system.
If you are unsure, say N here.
config USB_OTG
bool
depends on USB && EXPERIMENTAL
select USB_SUSPEND
default n
config USB_OTG_WHITELIST
bool "Rely on OTG Targeted Peripherals List"
depends on USB_OTG
default y
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".
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
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.
