UDEVD(8)

NAME
udevd - udev event serializer daemon
udevsend - sends the event to udevd

SYNOPSIS
udevsend hotplug-subsystem

The environment must provide the following variables:

ACTION
    add or remove signifies the connection or disconnection of a device.

DEVPATH
    The sysfs devpath of the device without the mountpoint but a leading slash.

SEQNUM
    The sequence number of the event provided by the kernel. If unset, the event bypasses the queue and will be executed immediately.

DESCRIPTION
udevd allows the serialization of hotplug(8) events. The events generated by the kernel may arrive in random order in userspace, that makes it neccessary to reorder them.
udevd takes care of the kernel supplied sequence number and arranges the events for execution in the correct order. Missing sequences delay the execution of the following events until a timeout is reached.
For each event a udev(8) instance is executed in the background. All further events for the same device are delayed until the execution is finished. This way there will never be more than one instance running for a single device at the same time.
udevd receives the events from udevsend which is called by hotplug(8). If udevd isn't already running, udevsend will start it.

SEE ALSO
udev(8), udevinfo(8), hotplug(8)

AUTHORS
udevd was developed primarily by Kay Sievers <kay.sievers@vrfy.org>, with much help from others.