From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brian King Subject: mpt2sas DMA mask Date: Tue, 12 May 2015 17:07:36 -0500 Message-ID: <555279A8.6060906@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from e35.co.us.ibm.com ([32.97.110.153]:50521 "EHLO e35.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932989AbbELWHl (ORCPT ); Tue, 12 May 2015 18:07:41 -0400 Received: from /spool/local by e35.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 12 May 2015 16:07:41 -0600 Received: from b03cxnp07029.gho.boulder.ibm.com (b03cxnp07029.gho.boulder.ibm.com [9.17.130.16]) by d03dlp01.boulder.ibm.com (Postfix) with ESMTP id 28CE01FF0023 for ; Tue, 12 May 2015 15:58:49 -0600 (MDT) Received: from d03av03.boulder.ibm.com (d03av03.boulder.ibm.com [9.17.195.169]) by b03cxnp07029.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t4CM7c0053608454 for ; Tue, 12 May 2015 15:07:38 -0700 Received: from d03av03.boulder.ibm.com (localhost [127.0.0.1]) by d03av03.boulder.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t4CM7cqo001526 for ; Tue, 12 May 2015 16:07:38 -0600 Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Sreekanth Reddy , Benjamin Herrenschmidt Cc: linux-scsi , linuxppc-dev The mpt2sas driver was changed late last year in that it now requests a 64 bit DMA mask, then requests a 32 bit coherent DMA mask, then later requests a 64 bit coherent DMA mask. This was 5fb1bf8aaa832e1e9ca3198de7bbecb8eff7db9c. This breaks 64 bit DMA support for mpt2sas on Power and we always fall back to using 32 bit DMA. Looking at the commit log, it looks like this was an intentional change. Ben - you had a patch set you had posted to the list back in Feb of this year, but it doesn't look like it got merged. https://lists.ozlabs.org/pipermail/linuxppc-dev/2015-February/125087.html This would fix the issue I'm seeing on mpt2sas. Do you plan to dust that patch set off and upstream it? Were there issues with it that still need to be resolved? Thanks, Brian -- Brian King Power Linux I/O IBM Linux Technology Center