Subject: Re: Patch to add console scrollback support.
To: None <>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
List: tech-kern
Date: 06/04/2001 15:44:33
[responding to greywolf's response to me]

>> I've considered doing console switching *with* just storing the
>> bitmaps, for bitmap framebuffers; in particular I've wanted to be
>> able to switch away from an X session, which would mean doing
>> interesting things with mmap...a while ago, I did similar hacks in
>> the X server, but that would be X-only.
> Arguably, doing that as an X-only thing might be the way to go;

Not for me; I specifically want to switch away from an X session to a
non-X session.

> you really don't want to be storing 8x1152x900 bits per screen for
> the consoles,

On some of my machines I do :)

> I know this isn't Linux (thank the Gods for large favours!), but
> there's obviously something they managed to implement correctly.  I
> don't see too terribly much impeding us from doing the same.  Perhaps
> we're not initializing the palette correctly (at least on the CG6)?

What does the palette have to do with it?  (Perhaps I just don't
understand your value of "correctly".)

> If someone wants to send me a 13W3-M/VGA-F adapter, I can poke my
> nose into at least the cg6 RASTERCONSOLE stuff and see if I can at
> least get the ANSI colour stuff working.

This sounds as though your "correctly" includes "ANSI colour", by which
you presumably mean "ISO colour values for the ANSI SGR sequence".

If so, well, more power to you, but I'll disable that option. :-)

[now responding to eeh's response to greywolf]

> Uh, 1MB (for 8x1152x900) wired kernel memory just to store a backup
> bitmap image?  ``Just say "No."''

Who said anything about "wired"?  I see no reason it couldn't be
pageable (though if I were doing it I'd also have a way of doing the
switching that says "don't even try to preserve the old framebuffer",
primarily for use as a trouble-investigatory measure).

> RASTERCONSOLE.  Ick.  Tried it.  Didn't like it.  

> (If you think you have performance issues with the console,
> RASTERCONSOLE won't help much.  Remember, to scroll the console
> requires moving 1MB of memory.

You obviously haven't tried RASTERCONSOLE on a cg6 with my cg6 hardware
blitter support in place.  It makes an *immense* difference.  (Though I
have seen some cg6s on which it doesn't work until you start X for the
first time since power-on; there's clearly some sort of initialization
I'm not getting right.)

I thought I'd gotten that into the main tree, but it appears not.  I'll
be happy to send a copy to anyone who cares to ask for one; it's been
over a year or so since I updated my patches to match -current, but it
probably wouldn't be too tough to merge them in.

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