wiki:ImageDevManager

Introduction

I noticed that there are migrations from devtmpfs to udev or from udev to devtmpfs in openembedded. Here is a page to document that.

Features or Issues

Features/Issues? udev devtmpfs
startup speed slower faster
available since old kernels 2.6.32[1]
/dev/cmt support on nokia900 yes no
can start bluetoothd yes no
Firmware loading done by udev itself done by fsodeviced
/dev/input/ symlinksdone by udev no

Reasons to stay away from udev

  • Slows down the boot process significantly
  • Handles things the kernel is better suited for (i.e. creating device nodes)
  • Breaks in strange ways every couple of releases
  • Splits our chain of responsibility (i.e. starting of services, which is the domain of fsousaged)
  • Rules syntax

Dependencies on udev

Some packages can depend or not on udev:

  • Xorg (there is the choice between: hal/udev/none)

References