From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758961AbaCTQKu (ORCPT ); Thu, 20 Mar 2014 12:10:50 -0400 Received: from moutng.kundenserver.de ([212.227.17.10]:55791 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751599AbaCTQKs (ORCPT ); Thu, 20 Mar 2014 12:10:48 -0400 From: Arnd Bergmann To: linux-arm-kernel@lists.infradead.org Cc: Ben Dooks , Russell King , linux-sh@vger.kernel.org, "linux-pci@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Magnus Damm , Ben Dooks , Bjorn Helgaas , Simon Horman Subject: Re: DMABOUNCE in pci-rcar Date: Thu, 20 Mar 2014 17:09:57 +0100 Message-ID: <5527822.QYtFYiIpiW@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.11.0-18-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: <532B0384.1000400@codethink.co.uk> References: <201402241200.21944.arnd@arndb.de> <5165962.7bqj51B15Z@wuerfel> <532B0384.1000400@codethink.co.uk> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V02:K0:paDq5zOBhfbvs/aqwF7nGfXdIXe6vmTdBR9YaKlaKek CvYyTRI+5cmLFOerX9LwczreIPHJeLr4Ud5gcehTOLLt0RCcBn sq+OQibodCKkZHDjeB4MSxklBYrp0ycflWJcRYmdYgC0ihY36y lZjw+AhKxZ/GbjU8bv/RHXb06lh6fQ/xWreDfWmUdT8IYnQICH NCElN7aGsmV3uBW32PBgocBBWn6kAm2UC3+TLP8miGC4XIAR2h 3wEzD69Zt937x19JD9vwcMMxYXG3Qdis0qFAmlicSgkM0g7zmN sLA0inoX5yOZ6n/79UZjUlHrOXbhhmDJ5pYWyVdDgFGVQ8TgGd WaR6N3t8FaUq2gbaoPwA= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 20 March 2014 16:04:36 Ben Dooks wrote: > On 26/02/14 20:57, Arnd Bergmann wrote: > > On Wednesday 26 February 2014 12:48:17 Bjorn Helgaas wrote: > >> On Mon, Feb 24, 2014 at 4:00 AM, Arnd Bergmann wrote: > >>> Hi Magnus, > >>> > >>> I noticed during randconfig testing that you enabled DMABOUNCE for the > >>> pci-rcar-gen2 driver as posted in this patch https://lkml.org/lkml/2014/2/5/30 > >>> > >>> I didn't see the original post unfortunately, but I fear we have to > >>> revert it and come up with a better solution, ... > >> > >> Sounds like I should drop the following patches from my pci/host-rcar > >> branch for now? > >> > >> PCI: rcar: Add DMABOUNCE support > >> PCI: rcar: Enable BOUNCE in case of HIGHMEM > >> PCI: rcar: Make the Kconfig dependencies more generic > > > > Sounds good to me. The last patch is actually fine, but you'll have to > > fix the context to apply it without the other two. > > As a note, if we now boot a Lager with DT on 3.14-rc3 series the USB > controllers no longer work with full 2GiB RAM enabled in the device > tree. Did it work before these patches got applied initially? > Could we work around this by having 1GiB of memory defined in the > 32bit memory and then add the rest of the 3GiB from the >32bit > area via LPAE? Will the kernel ever try to allocate DMA memory from > anything >32bit? You can solve the case for dma_alloc_coherent() this way, or by setting the mask correctly. It won't help you for dma_map_* though, which still requires someone to add support for swiotlb or using an IOMMU if present. Arnd