udevd(8) -- Linux man page



udevd, udevdsend - udev event serializer daemon and udev event sender  


udevsend hotplug-subsystem

The environment must provide the following variables:

add or remove signifies the connection or disconnection of a device.
The sysfs devpath of the device without the mountpoint but a leading slash.
The sequence number of the event provided by the kernel. If unset, the event bypasses the queue and will be executed immediately.


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.  


udev(8), udevinfo(8), hotplug(8)  


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