From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: [PATCH V2 1/3] scsi: mptxsas: try 64 bit DMA when 32 bit DMA fails Date: Tue, 10 Nov 2015 12:05:20 -0800 Message-ID: <1447185920.2187.53.camel@HansenPartnership.com> References: <1447034266-28003-1-git-send-email-okaya@codeaurora.org> <5349261.sTnZTFhKWB@wuerfel> <56421610.50005@codeaurora.org> <4982446.ZlJVrezq1Y@wuerfel> <56422725.7040809@codeaurora.org> <1447180034.2187.20.camel@HansenPartnership.com> <56424200.9080406@codeaurora.org> <1447184611.2187.45.camel@HansenPartnership.com> <56424BF4.2040207@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <56424BF4.2040207@codeaurora.org> Sender: linux-scsi-owner@vger.kernel.org To: Sinan Kaya Cc: Arnd Bergmann , linux-arm-kernel@lists.infradead.org, Abhijit Mahajan , Nagalakshmi Nandigama , linux-scsi@vger.kernel.org, jcm@redhat.com, timur@codeaurora.org, 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 List-Id: linux-arm-msm@vger.kernel.org On Tue, 2015-11-10 at 14:56 -0500, Sinan Kaya wrote: > > On 11/10/2015 2:43 PM, James Bottomley wrote: > > The Issue, as stated by LSI is > > > > Initially set the consistent DMA mask to 32 bit and then change > > it > > to 64 bit mask after allocating RDPQ pools by calling the > > function > > _base_change_consistent_dma_mask. This is to ensure that all the > > upper 32 bits of RDPQ entries's base address to be same. > > > > Need somebody from mpt to confirm that this behavior is still valid for > the recent cards besides altix. OK, you don't seem to be understanding the problem: the Altix isn't a LSI card, it was a SGI platform. It was the platform where we first discovered the issue that a lot of storage cards didn't work because it by default had no memory below 4GB. The reason coherent masks were introduced was initially so the Altix could manufacture and manage a region of memory in the lower 4GB region and we would guarantee to make allocations from it so the storage cards would then work on that platform. I thought the Altix was a historical relic because after they disappeared, there was no other platform with this issue ... until you came along. James