From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?B?Q2hyaXN0aWFuIEvDtm5pZw==?= Subject: Question on UAPI for fences Date: Fri, 12 Sep 2014 15:23:22 +0200 Message-ID: <5412F3CA.9060306@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from na01-bn1-obe.outbound.protection.outlook.com (mail-bn1bon0133.outbound.protection.outlook.com [157.56.111.133]) by gabe.freedesktop.org (Postfix) with ESMTP id D3D976E00F for ; Fri, 12 Sep 2014 06:57:44 -0700 (PDT) List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: "dri-devel@lists.freedesktop.org" , Maarten Lankhorst , Jerome Glisse Cc: gpudriverdevsupport@amd.com List-Id: dri-devel@lists.freedesktop.org Hello everyone, to allow concurrent buffer access by different engines beyond the multiple readers/single writer model that we currently use in radeon and other drivers we need some kind of synchonization object exposed to userspace. My initial patch set for this used (or rather abused) zero sized GEM buffers as fence handles. This is obviously isn't the best way of doing this (to much overhead, rather ugly etc...), Jerome commented on this accordingly. So what should a driver expose instead? Android sync points? Something else? Please discuss and/or advise, Christian.