Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752834AbcDKHzr (ORCPT ); Mon, 11 Apr 2016 03:55:47 -0400 Received: from nat-hk.nvidia.com ([203.18.50.4]:64095 "EHLO hkmmgate102.nvidia.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752377AbcDKHzq (ORCPT ); Mon, 11 Apr 2016 03:55:46 -0400 X-PGP-Universal: processed; by hkpgpgate101.nvidia.com on Mon, 11 Apr 2016 00:55:43 -0700 Subject: Re: Nouveau crashes in 4.6-rc on arm64 To: Robin Murphy , , , References: <57064992.1060509@arm.com> <570737F5.30105@nvidia.com> <5707FC9F.50905@arm.com> <570B50B4.4020304@nvidia.com> CC: From: Alexandre Courbot Organization: NVIDIA X-Nvconfidentiality: public Message-ID: <570B587A.5090509@nvidia.com> Date: Mon, 11 Apr 2016 16:55:38 +0900 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.2 MIME-Version: 1.0 In-Reply-To: <570B50B4.4020304@nvidia.com> X-Originating-IP: [10.19.57.128] X-ClientProxiedBy: DRBGMAIL103.nvidia.com (10.18.16.22) To HKMAIL103.nvidia.com (10.18.16.12) Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 546 Lines: 10 On 04/11/2016 04:22 PM, Alexandre Courbot wrote: > ... or maybe we could just unconditionally sync all buffers and let the > DMA API abstract this away. My concern is that on coherent architectures > we would still need to loop over all the pages for nothing, as I don't > think the loop (see e.g. nouveau_bo_sync_for_cpu in nouveau_bo.c) can be > optimized away by the compiler. Looking at the code it actually turns out we are already calling the sync functions on coherent buses anyway, so maybe we have little reasons to keep this at all?