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DateFri, 11 Aug 2000 09:20:35 +0200
FromMichael Westermann <>
SubjectRe: design-question serial-driver + predefined ldisc - Nuber
Hallo,

On Thu, Aug 10, 2000 at 10:26:50AM -0400, Theodore Ts'o wrote:
>    I hav a projekt for POS-Systeme with a few driver's that
>    all use a protokoll over the serial device. 
>    I think it is a goo idea when i use the ldisc mechanism 
>    from the tty driver. 
> 
>    My problem is that the ldiscs array in tty_io.c is static
>    predefined. I have 3 to 10 protokoll's over this mechnism. 
> 
>    I think it is a good idea, to create a dynamic part on the ldiscs 
>    structure. 
> 
> So your idea is to have a range of line discplines from N_LDDYN and
> NR_LDISCS would be dynamically allocated?  It seems like a good concept,
> but (a) not for Linux 2.4, (b) don't overload the return value of
> tty_register_ldisc (it's ugly, ugly, ugly), and (c) the dynamic line
> discplines (and arguably all of the other line discplines, in the long
> run) should probably use an ASCII string instead of a number to address
> them.
> 
> Linus hates magic numbers, and while in some cases they are necessary,
> line discplines are a perfect example of where a new ioctl where you
> pass in a 32 byte character array containing a null-terminated string
> naming the line discpline you want is almost certainly the Right Thing.
> Unfortunately, it's not for 2.4, but that's probably the right approach
> to use, and hopefully we can merge a patch like that in once the 2.5
> development opens.
> 

I'm agree this, it is a very good Idea, to use Stings ;-). 
OK in this time, I use (missbrow) a existing descriptor over the 
modul-alias mechanism. The driver is very very spezially Protokoll,
with a z8530 driver on i386. I plan in the next time, to merge 
the 4..5 z8530 drivers to one modul, but i have only a i386 box.

thank's 


Michael 




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