Messages in this thread | | | Date | Wed, 6 Oct 1999 09:02:45 -0400 (EDT) | From | George <> | Subject | Re: USB device allocation |
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On Wed, 6 Oct 1999, Nathan Hand wrote:
>Agreed. Getting rid of devfs (the dynamic filesystem) makes devfs (the >concept of dynamic /dev) more acceptable to more punters, and honestly >doesn't lose all that much functionality. Modules contact devfsd when >they need a node. The daemon creates/deletes nodes as needed on a real >filesystem using the policy laid out via /etc/devfsd.conf.
Why contact a daemon? Have modprobe run 'MAKEDEV' when it's done. MAKEDEV can already read /proc/devices to automagically figure out many devices to configure. It's also mentioned in the man-page to have autodelete support but I imagine that it doesn't right now since it is missing a comprehensive list of nodes that should exist.
> - The /dev directory is updated in user space, not kernel space.
MAKDEV.
> - You can just turn off the daemon, old behaviour is restored.
Don't run MAKEDEV.
> - Kernel modifications are minimal (changes to init/cleanup_module).
No kernel modification.
> - Major/minors can be assigned dynamically by drivers, avoids GUID.
Maybe, but not currently. If it was exported by kernel in /proc, yes. Currently only the majors are.
> - Topology rules for USB can be over-engineered totally in user space.
Believe so but fuzzy on the intent behind the above.
> - The policy for naming nodes moves to user space, hpa is happy.
MAKEDEV
> - Persistence of nodes is maintained by the filesystem, tso is happy.
MAKDEV
> - Devfs gets into the kernel, everyone else in the world is happy.
No need. /dev on a ramdisk. Run 'MAKEDEV update' when you boot.
-George Greer
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