Subject: Re: Console Magic redux
To: None <email@example.com, firstname.lastname@example.org, torek@BSDI.COM>
From: None <email@example.com>
Date: 11/27/2000 15:55:55
>Drivers may think they are the console but be very wrong.
>On some machines, like SPARC, one device can register as the console
>only to find another device has replaced it later.
Erm, are consoles dynamic, then, or are these devices just
mistaken to begin with?
The console can be one of:
A serial port driver
A keyboard line discipline layered on top of a serial
A keyboard driver
The PROM console driver.
The PROM console driver attaches only if no other device has claimed
A serial driver on the console input path will think it's the console
even if it is attached to a keyboard. If it is attached to a keyboard
then the keyboard driver really should be the console, but it requires
the serial driver's I/O routines to operate.
Finally, there is the case with mismatched input and output. We
actually support this configuration so you can have two separate
drivers as the console, one for input and one for output.
(I personally still think the "right" way to handle console-ness
is to autoconfig as usual, then have the top-level kernel open
the appropriate I/O stream -- which may even be a network connection
-- and hold it open forever as "the console". But this is another
How does the top-level kernel determine which I/O stream should be