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/ symlinks | done 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)
