[Buildroot] Using udev, non-static /dev, and ramfs (or tmpfs)

Rob Landley rob at landley.net
Sat Oct 21 20:22:28 UTC 2006

On Saturday 21 October 2006 2:34 pm, don wrote:
> I have a buildroot system that has been working fine (thanks) using
> a static /dev in a ramfs rootfs.  Now I want to add a USB device and it 
> seems like I should let udev etc. handle it.

I'd recommend mdev from busybox, but then I wrote it. :)

> However udev cannot make entries in a read-only /dev.
> Is there a simple recipe for mounting /dev as writable?

mount -t tmpfs /dev /dev
> There are several compilcations:
> 	Normally to mount with ramfs I'd use /dev/ram*. 

No, that's a ram disk not ramfs.  A ramfs (or tmpfs) doesn't have backing 

Install a recent busybox (1.2.2 would be best, once I get that up. :)

To populate dev:

  mdev -s

To handle hotplug events:

  echo "/sbin/mdev" > /proc/sys/kernel/hotplug

"Perfection is reached, not when there is no longer anything to add, but
when there is no longer anything to take away." - Antoine de Saint-Exupery

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