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Re: clearing the screen -> framebuffer insanity

On Tue, 2002-12-10 at 00:47, Pigeon wrote:
> On Mon, Dec 09, 2002 at 06:19:21PM -0800, Joe Riel wrote:
> > Just wondering, what is a framebuffer console?
> > And how would I know whether I was using one?
> It means that your text mode screens, instead of being a real text
> mode, are actually graphics mode, with characters being displayed by
> writing bitmaps to the screen. It exists to allow Linux to be usable
> on non-PC machines that don't know what VGA is.
> As a side effect it allows PCs to be configured to run pseudo-'text' modes
> other than the standard 80x25. So does SVGATextMode, but using a real text
> mode screen, so without the large overhead.
> Unfortunately the appearance of framebuffer mode meant that whoever
> was responsible for SVGATextMode dropped it in 1999, with the result
> that newer video cards may be unsupported. I note that kernel 2.4.20
> only has framebuffer listed under the "experimental options", so maybe
> SVGATextMode will get going again?
> If you have a PC, and want a change from 80x25, use SVGATextMode. If
> it doesn't support your video card, hack it until it does.
> To find out if you're running framebuffer: dmesg | grep -i vga
> I think you get 'fb' somewhere in the output if you're using
> framebuffer.
> Pigeon

I don't believe I've ever seen the framebuffer code on the 2.4.* kernel
sources be listed outside Experimental (I've had the source of most
kernels of the 2.4 series, except for the "very quickly replaced due to
ugly bugs" versions.) As such, I'm very surprised to hear that so many
distributions are putting out stock kernels with it - just installed Red
Hat on a client's workstation (his choice, he'd picked up a set of
linuxcentral CDs and knows that I charge for burning images,) and iirc,
it switches on a generic framebuffer as part of running its installation
toy, er, system. It did support his Riva TNT card cleanly though, which
surprised me.

I know that atyfb was still capable of hanging my system on simply
scrolling a console as recently as 2.4.12, so I can see classifying it
substantively as "Experimental". Someday I might even look at the idea
of putting old, diskless boxes on as a network for my machine as X
terminals and look at whether a single kernel can support multiple
different cards with framebuffers ;)
ML Kahnt New Markets Consulting
Tel: (613) 531-8684 / (613) 539-0935
Email: kahnt@hosehead.dyndns.org

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