linux-kernel - Re: console font limits

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Message-ID: <Pine.LNX.4.64.0705031754410.4727@anakin>
Date:	Thu, 3 May 2007 17:56:35 +0200 (CEST)
From:	Geert Uytterhoeven <geert@...ux-m68k.org>
To:	Jan Engelhardt <jengelh@...ux01.gwdg.de>
Cc:	Albert Cahalan <acahalan@...il.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	"Antonino A. Daplas" <adaplas@...il.com>,
	linux-kernel <linux-kernel@...r.kernel.org>, aeb@....nl
Subject: Re: console font limits

On Thu, 3 May 2007, Jan Engelhardt wrote:
> On May 3 2007 10:14, Albert Cahalan wrote:
> > On 5/3/07, Jan Engelhardt <jengelh@...ux01.gwdg.de> wrote:
> >> On May 3 2007 02:17, Albert Cahalan wrote:
> >
> >> > Those sizes are unreadable on the 200 dpi OLPC XO screen,
                                                 ^^^^
> >> 
> >> Hm that should have read, for you:
> >> I don't object implementing support for larger sizes.
> >> (But I wonder how that should work without FB/CVIDIX/SVGA/VESA
> >> extensions.)
> >> 
> >> Note that I was assuming that no FB is used:
> >
> > I'm assuming that the FB is used. Neither of my two
> > computers can do VGA text mode.
> 
> Some non-x86 boxes like sparc?

OLPC is x86 ;-)

> > Then, as with X, you have problems with kernel messages.
> > Reliably sending printk through a userspace console is not
> > even possible. (consider a panic, OOM, or runaway RT task)
> 
> Actually, the kernel could just "jump in". That is, when you start
> in fb mode, you get the regular 8x16 vga font - on your choice of
> resolution, and can also set it with setfont. So far so nice.
> Now, when you start fbiterm -- for example to read CJK --, fbiterm
> presents you with what looks like a 12x24 font. Also good.
> It _looks_ to me like fbiterm does the drawing itself; ok too.
> Now when the kernel is oopsing, it could just spew out the oops
> trace in the regular font (vga8x16 or in case you use CONFIG_FONTS,
> then that), possibly obstructing some output generated by fbiterm,
> but in case of oops, I think this is ok.

Funny, that's exactly how kernel messages where handled in the early
fbdev days: just draw them to the frame buffer, whatever mode it is
in...
Just like on the SunOS boxes ;-)

Put people didn't like that, and disabled text output when the console
is in KD_GRAPHICS mode...

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds
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