Re: (Semi-random) thoughts on device tree structure and devfs

[Masao Uebayashi <uebayasi%gmail.com@localhost>]

On Fri, Mar 12, 2010 at 6:00 PM, Iain Hibbert <plunky%rya-online.net@localhost> 
wrote:
> On Fri, 12 Mar 2010, David Holland wrote:
>> Line disciplines are a bad example, because they're a prehistoric kind
>> of hacked-up bus attachment and as such ought to be rototilled out of
>> existence.
>
> Well, line discipline is a solution to a problem, which is that we want a
> 'device' in the kernel but the device is not directly accessible and
> communicates to us through a serial protocol.
>
> You can say its a bad idea all you like, but unless you suggest an
> alternative solution that doesn't help to remove it.
>
> One alternative is to move the translator out of the kernel, eg instead of
> using the pppd(8) which needs complicated hooks, import userland ppp(8) as
> per FreeBSD which IIRC provides a tap(4) interface. The argument against
> that is probably not as strong as it once was as even embedded devices
> these days can be several orders of magnitude faster than the computers
> that were prevalent when pppd(8) was written. But then, data rates have
> improved also - pppd(8) runs on my uhso(4) dongle at up to 180KiB/s and I
> expect there would still be objections to removing it.
>
> Any other solutions you would like to propose?

Although I have 0 knowledge & have no time to learn tty/line disc at
the moment, I fully support to fix those *now*.

You need struct device.  You understand how data/control flow.  I
think it's perfectly reasonable to make it a device as a "function".

Masao