RE: Serial custom speed deprecated?

[David Woodhouse <dwmw2@infradead.org>]

On Thu, 2006-08-24 at 14:19 +0100, Alan Cox wrote:
> Actually to do this right we have to make a decision or two
> 
> The POSIX way of handling this requires the speeds are in the termios
> structure "somewhere". We can't easily implement cfgetispeed/cfgetospeed
> unless we grow the termios structure in the kernel and issue 3 new
> ioctls (keeping the others as trivial translations) and then bumping
> glibc and the kernel to do the right thing.
> 
> The alternative is that we provide an extra pair of speed ioctls and
> glibc does the magic to hide this lot while providing a termios with the
> new fields itself.
> 
> Whichever way we go glibc already has the fields present and the
> libc<->application API appears to be unchanged by this.
> 
> I'd rather we went the way of extending our termios to include c_ispeed,
> c_ospeed values. The code isn't hard for the remapping of the old ones
> and it avoids extra ioctls and the corner case races between two speed
> sets that occur if they are two ioctls.

Agreed. Some architectures have c_[io]speed in their struct termios
already, in fact, but others would need new ioctls for it.

-- 
dwmw2