question about misc char devices, and relationship with udev

Greg KH greg at
Sat Apr 23 11:09:40 EDT 2011

On Sat, Apr 23, 2011 at 09:45:39AM -0400, Robert P. J. Day wrote:
> but here's the confusing part.  who or what created that /dev entry?
> i always thought that was the job of udev, but i never added any udev
> rule for this new driver.  so how did that new /dev file come to be?
> is there some sort of generic udev rule that would have handled this?

Yes there is, udev took the default kernel name and created the device
node for it.  The misc device is exported in sysfs automatically by the
misc core code, as you pointed out with the call to device_create().

And, in newer versions of your distro, devtmpfs created the device node,
udev just set the permissions on it.

Hope this helps,

greg k-h

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