Re: [Qemu-devel] [PATCH 26/29] vmsvga: Add basic support for display topology

[Gerd Hoffmann]

  Hi,

> +    case SVGA_REG_DISPLAY_WIDTH:
> +        if ((s->display_id == 0) || (s->display_id == SVGA_ID_INVALID))
> +            ret = s->new_width ? s->new_width : surface_width(surface);
> +        else
> +            ret = 0;
> +        break;
> +    case SVGA_REG_DISPLAY_HEIGHT:
> +        if ((s->display_id == 0) || (s->display_id == SVGA_ID_INVALID))
> +            ret = s->new_height ? s->new_height : surface_height(surface);
> +        else
> +            ret = 0;
> +        break;

What is the purpose of these registers?  Hint for the guest about the
host display size?  If so you probably want wire up a callback for
GraphicHwOps->ui_info.  This will be called on display changes (i.e.
user resizes qemu gtk window).  See virtio_gpu_ui_info() for an example.

cheers,
  Gerd