From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AF18FC04AAF for ; Thu, 16 May 2019 13:21:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8025D20818 for ; Thu, 16 May 2019 13:21:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727445AbfEPNVk (ORCPT ); Thu, 16 May 2019 09:21:40 -0400 Received: from foss.arm.com ([217.140.101.70]:45460 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726528AbfEPNVk (ORCPT ); Thu, 16 May 2019 09:21:40 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A2C4F1715; Thu, 16 May 2019 06:21:39 -0700 (PDT) Received: from [10.1.196.69] (e112269-lin.cambridge.arm.com [10.1.196.69]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 625313F703; Thu, 16 May 2019 06:21:37 -0700 (PDT) Subject: Re: [PATCH v4 0/8] Allwinner H6 Mali GPU support To: Robin Murphy , Rob Herring , =?UTF-8?B?Q2zDqW1lbnQgUMOpcm9u?= Cc: Mark Rutland , devicetree , Neil Armstrong , David Airlie , linux-kernel , dri-devel , Maxime Ripard , linux-sunxi , Rob Herring , Chen-Yu Tsai , linux-arm-kernel References: <20190512174608.10083-1-peron.clem@gmail.com> <20190513151405.GW17751@phenom.ffwll.local> <3c2c9094-69d4-bace-d5ee-c02b7f56ac82@arm.com> From: Steven Price Message-ID: Date: Thu, 16 May 2019 14:21:35 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 16/05/2019 12:19, Robin Murphy wrote: [...] > I was expecting to see a similar behaviour to my T620 (which I now > assume was down to 64-bit job descriptors sort-of-but-not-quite working) > but this does look a bit more fundamental - the fact that it's a level 1 > fault with VA == head == tail suggests to me that the MMU can't see the > page tables at all to translate anything. I really hope that the H6 GPU > integration doesn't suffer from the same DMA offset as the Allwinner > display pipeline stuff, because that would be a real pain to support in > io-pgtable. Assuming you mean the case where the physical address (as seen by the CPU) is different from the dma address (as seen by the GPU), then I highly doubt it because mali_kbase doesn't support it: [from kbase_mem_pool_alloc_page() in mali_kbase_mem_pool.c]: dma_addr = dma_map_page(dev, p, 0, PAGE_SIZE, DMA_BIDIRECTIONAL); if (dma_mapping_error(dev, dma_addr)) { __free_page(p); return NULL; } WARN_ON(dma_addr != page_to_phys(p)); That being said it's quite possible there could be something in the bus which needs configuring to make this work - in which case your best bet is to look at the vendor kernel and see if anything extra is poked when the Mali driver is loaded. Steve