Re: AW: AW: [DDL-ML] Programmiergleis

[Harald Barth <haba@pdc.kth.se>]

> Perhaps it is posible to make it a command line option to set the serial
> nmra frequency to 38400. I don't have to change the source code each time
> there is a new version.

Of course this should go into the source somehow. For two reasons this is
not as easy as I would like it to be:

1) The ioctl that you change the behaviour of 38400 baud with seems to
take a struct as an argument. I havn't quite succeeded to do this
independent of the Linux kernel version. I think I have to look at the
setserial source :-(

2) The Märklin timing uses "real" 38400 - If we go for special user defined
tty speeds, we need to juggle with the divisor there, too. At least if you
want to run DDL in mixed (-M on -N on) mode.

3) If you have special card (quite unusual fortunately) with another
base frequency your divisors will be wrong. Of course you can set test
and correct. The uart16550_midi device driver does that. But there we
go again with special device driver topic which I didn't want to touch
until I got a prototype.

Harald.