Re: [Qemu-devel] [PATCH] [RFC] Variable video ram size option

[Jamie Lokier <jamie@shareable.org>]

Rene Rebe wrote:
> >I think the Linux "vesafb" driver uses all available VRAM for
> >scrolling in draws-text-on-graphic-framebuffer mode.
> 
> But only with ypan enabled, which wasn't the default when I took a  
> look the last time.

That's right.

I don't know why "ypan" is off by default; it's hard to imagine it not
working on anything vaguely VBE-like, or even VESA (pre-VBE), since a
lot of DOS games need the panning feature to work for double/triple
buffering.

If you're using Linux guest with VESA framebuffer console, rather than
a text-mode console, I'd recommend kernel boot option "video=vesafb:ypan",
to save considerable CPU when scrolling the console.

I don't know if "video=vesafb:ywrap" works on the QEMU VBE emulation.
That'd be better.

-- Jamie





>  -- René Rebe - ExactCODE GmbH - Europe, Germany, Berlin
> http://exactcode.de | http://t2-project.org | http://rene.rebe.name