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Date: Fri, 10 Aug 2018 11:56:54 +0200
From: Gerd Hoffmann <kraxel@redhat.com>
Message-ID: <20180810095654.drs4fwswdakktqbw@sirius.home.kraxel.org>
References: <1533815202-11967-1-git-send-email-liran.alon@oracle.com>
	<1533815202-11967-27-git-send-email-liran.alon@oracle.com>
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In-Reply-To: <1533815202-11967-27-git-send-email-liran.alon@oracle.com>
Subject: Re: [Qemu-devel] [PATCH 26/29] vmsvga: Add basic support for
 display topology
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To: Liran Alon <liran.alon@oracle.com>
Cc: qemu-devel@nongnu.org, pbonzini@redhat.com, mtosatti@redhat.com, rth@twiddle.net, habkost@redhat.com, Leonid Shatz <leonid.shatz@oracle.com>

  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