Re: [SeaBIOS] [PATCH] vga: Don't advertise multiple pages for lfb modes.

[Kevin O'Connor]

On Mon, Sep 09, 2013 at 09:24:40AM +0200, Gerd Hoffmann wrote:
> Seems win8 doesn't like it.  With this patch win8 guests allow
> to set the screen resolution to something != 1024x768.
> Signed-off-by: Gerd Hoffmann
>
> vgasrc/vbe.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/vgasrc/vbe.c b/vgasrc/vbe.c
> index d962333..b0ee002 100644
> --- a/vgasrc/vbe.c
> +++ b/vgasrc/vbe.c
> @@ -142,6 +142,7 @@ vbe_104f01(struct bregs *regs)
>          framebuffer = GET_GLOBAL(VBE_framebuffer);
>          if (framebuffer)
>              mode_attr |= VBE_MODE_ATTRIBUTE_LINEAR_FRAME_BUFFER_MODE;
>    pages = 1;
>    break;
> }
>    SET_FARVAR(seg, info->mode_attributes, mode_attr);

That's odd.  According to the vbe spec:

The NumberOfImagePages field specifies the "total number minus one
(-1)" of complete display images that will fit into the frame buffer
memory.

The existing code matches the original bochs vbe code and matches what
the spec says.  I'm surprised win8 would require such an odd value.

-Kevin