Re: Serial design

[Vojtech P. <vo...@su...>]

On Thu, Dec 27, 2001 at 02:20:39AM -0500, Andrew E. Mileski wrote:

> > > >    The second class is using the bus like the PCI/PNP layer to find out
> > > > what got attached.
> > >
> > > This sounds a somewhat Microsofty solution.  Do we really want the kernel
> > > sending stuff like 'AT' commands at various baud rates to the connected
> > > machine, which might be waiting for you to "press any key" after changing
> > > the floppy?
> > 
> > I never said anything about sending AT commands.
> 
> Though I hate to point this out, there is a spec for a serial PnP protocol,
> It doesn't confuse modems or terminals, as it twiddles the RTS/CTS lines.

It confuses serial UPSes. Some of them switch the computer off during
the PnPCom evaluation. ;)

> Yes, Microsoft developed it.  Microsoft serial mice should supoort it.

Actually, they don't. They ignore the line twiddling and just send the
PnP string at powerup (when DTR comes up for long enough to provide
power to the mouse controller chip.)

Most later serial modems do support the PnPCom evaluation, though.

Actually almost any serial device can be identified quite well, but I
don't think this should be done inside the kernel.

-- 
Vojtech Pavlik
SuSE Labs