Path: csiph.com!news.mixmin.net!eternal-september.org!feeder.eternal-september.org!aioe.org!bofh.it!news.nic.it!robomod From: Timur Tabi Newsgroups: linux.kernel Subject: Re: [PATCH V2 1/3] scsi: mptxsas: try 64 bit DMA when 32 bit DMA fails Date: Tue, 10 Nov 2015 18:10:01 +0100 Message-ID: References: X-Original-To: Arnd Bergmann , Sinan Kaya User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 22 Organization: linux.* mail to news gateway X-Original-Cc: linux-arm-kernel@lists.infradead.org, Abhijit Mahajan , Nagalakshmi Nandigama , linux-scsi@vger.kernel.org, jcm@redhat.com, "James E.J. Bottomley" , linux-kernel@vger.kernel.org, Sreekanth Reddy , Praveen Krishnamoorthy , cov@codeaurora.org, linux-arm-msm@vger.kernel.org, agross@codeaurora.org, MPT-FusionLinux.pdl@avagotech.com, Hannes Reinecke X-Original-Date: Tue, 10 Nov 2015 11:00:59 -0600 X-Original-Message-ID: <564222CB.3000701@codeaurora.org> X-Original-References: <1447034266-28003-1-git-send-email-okaya@codeaurora.org> <5349261.sTnZTFhKWB@wuerfel> <56421610.50005@codeaurora.org> <4982446.ZlJVrezq1Y@wuerfel> X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: csiph.com linux.kernel:1266646 On 11/10/2015 10:47 AM, Arnd Bergmann wrote: > What BenH was worried about here is that the driver sets different masks > for streaming and coherent mappings, which is indeed a worry that > could hit us on ARM as well, but I suppose we'll have to deal with > that in platform code. > > Setting both masks to 32-bit is something that a lot of drivers do, > and without IOMMU enabled, you'd hit the same bug on all of them. Also note that I think that on PowerPC, the mask is set to 32 by default for all devices. I don't think we do that on ARM64. So on PowerPC, some drivers get away with not explicitly setting the mask. -- Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/