From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1753614AbdESI5Q convert rfc822-to-8bit (ORCPT <rfc822;w@1wt.eu>);
        Fri, 19 May 2017 04:57:16 -0400
Received: from mx1.redhat.com ([209.132.183.28]:59774 "EHLO mx1.redhat.com"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1753396AbdESI5L (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Fri, 19 May 2017 04:57:11 -0400
DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 501F680C01
Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com
Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=kraxel@redhat.com
DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 501F680C01
Message-ID: <1495184222.627.46.camel@redhat.com>
Subject: Re: [RFC PATCH 6/6] drm/i915/gvt: support QEMU getting the dmabuf
From: Gerd Hoffmann <kraxel@redhat.com>
To: "Chen, Xiaoguang" <xiaoguang.chen@intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>,
        "Tian, Kevin" <kevin.tian@intel.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "zhenyuw@linux.intel.com" <zhenyuw@linux.intel.com>,
        "Lv, Zhiyuan" <zhiyuan.lv@intel.com>,
        "intel-gvt-dev@lists.freedesktop.org" 
        <intel-gvt-dev@lists.freedesktop.org>,
        "Wang, Zhi A" <zhi.a.wang@intel.com>
Date: Fri, 19 May 2017 10:57:02 +0200
In-Reply-To: <DD379D741F77464281CE7ED1CD7C12DE7065DDE5@SHSMSX101.ccr.corp.intel.com>
References: <1493372130-27727-1-git-send-email-xiaoguang.chen@intel.com>
         <DD379D741F77464281CE7ED1CD7C12DE6FC92D25@SHSMSX101.ccr.corp.intel.com>
         <DD379D741F77464281CE7ED1CD7C12DE6FC93698@SHSMSX101.ccr.corp.intel.com>
         <20170504100833.199bc8ba@t450s.home> <1493967331.371.53.camel@redhat.com>
         <20170505091115.7a680636@t450s.home>
         <DD379D741F77464281CE7ED1CD7C12DE70657AF3@SHSMSX101.ccr.corp.intel.com>
         <1494509273.17970.12.camel@redhat.com> <20170511094526.164985ee@w520.home>
         <DD379D741F77464281CE7ED1CD7C12DE706583BA@SHSMSX101.ccr.corp.intel.com>
         <20170511205829.672854c3@t450s.home> <1494580325.14352.57.camel@redhat.com>
         <20170512103828.4a1378a1@t450s.home>
         <DD379D741F77464281CE7ED1CD7C12DE706592D6@SHSMSX101.ccr.corp.intel.com>
         <20170515114409.414d1fdb@w520.home>
         <DD379D741F77464281CE7ED1CD7C12DE7065AA7D@SHSMSX101.ccr.corp.intel.com>
         <20170517154331.1b465f69@w520.home>
         <DD379D741F77464281CE7ED1CD7C12DE7065D1C0@SHSMSX101.ccr.corp.intel.com>
         <20170518085601.51e3296a@w520.home> <1495181089.627.33.camel@redhat.com>
         <DD379D741F77464281CE7ED1CD7C12DE7065DDE5@SHSMSX101.ccr.corp.intel.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8BIT
Mime-Version: 1.0
X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Fri, 19 May 2017 08:57:06 +0000 (UTC)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

  Hi,

> >We could also do it the other way around:  Instead of having the kernel returning
> 
> >the plane description userspace could pass it in, and the kernel throws -EINVAL in
> 
> >case it doesn't match due to things having changed meanwhile.
> 
> Or just return a dmabuf  based on the current plane ?

If gvt is able to hand out dma-bufs for inactive planes, then yes, we
can do this.  Have one ioctl where we pass in the plane id, get back a
plane description struct, and another where we pass in the plane
description struct and get back a dma-buf fd.

cheers,
  Gerd