Re: [Qemu-devel] [RFC] reduce reported VGA framebuffer to 8 MiB

[Alon Levy]

On Thu, May 26, 2011 at 09:44:38AM +0200, Gerd Hoffmann wrote:
>   Hi,
> 
> >>Which qemu version?  Which seabios&  vgabios version?
> >
> >qemu is the spice v36 branch with some unrelated patches.
> >seabios + vgabios upstream (seabios with 0x9000000 size hack).
> >
> >I can retest with qemu upstream.
> 
> Hmm, same here.
> 
> >>
> >>Windows xp booting in 4bit usually indicates VBE doesn't work at
> >>all, trying to enable vesafb in linux fails too then.
> >
> >VBE is working fine - attached are the VBE calls made in three cases:
> >  * -vga std
> >  * -vga qxl with the normal 64 MB framebuffer.
> >  * -vga qxl with 8 MB framebuffer (reported) (it's identical to the first)
> >
> >Note that this is all without the qxl driver working, but just with a 
> >windows xp install
> >with no qxl drivers.
> 
> Same here, works fine.  XP with SP3 btw, maybe this makes a difference.
> Can you try to boot linux with vga=0x314?

tested tinycore, looks like it sets VBE correctly without my patch, to a 16 bit 
color mode,
right after boot:
VBE: write index=0x3 val=0x10
VBE: write index=0x1 val=0x320
VBE: write index=0x2 val=0x258
VBE: write index=0x5 val=0x0
VBE: write index=0x4 val=0x41

And later Xvesa sets a 24bit color mode:
VBE: write index=0x3 val=0x18
VBE: write index=0x1 val=0x400
VBE: write index=0x2 val=0x300
VBE: write index=0x5 val=0x0
VBE: write index=0x4 val=0x41

And this is all while reporting the whole 64 MiB
VBE: read index=0xa val=0x400

But this just means linux handles it fine. I don't have a non SP3 handy but 
I'll try
to get one to test later. Not a really pressing issue.

> 
> cheers,
>   Gerd
> 
>