Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757178Ab0F3Tka (ORCPT ); Wed, 30 Jun 2010 15:40:30 -0400 Received: from mga01.intel.com ([192.55.52.88]:54192 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754743Ab0F3Tk3 (ORCPT ); Wed, 30 Jun 2010 15:40:29 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.53,514,1272870000"; d="scan'208";a="581556033" Message-ID: <4C2B9DAC.1030806@intel.com> Date: Wed, 30 Jun 2010 12:40:28 -0700 From: Dan Williams User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.10) Gecko/20100512 Thunderbird/3.0.5 MIME-Version: 1.0 To: "Woodhouse, David" CC: Chris Li , linux-kernel Subject: Re: BUG in drivers/dma/ioat/dma_v2.c:314 References: <4C29420D.2010406@intel.com> <4C2A8879.8010000@intel.com> <4C2AC55E.3040303@intel.com> <1277923422.16256.8.camel@localhost> In-Reply-To: <1277923422.16256.8.camel@localhost> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1541 Lines: 41 On 6/30/2010 11:43 AM, Woodhouse, David wrote: > On Wed, 2010-06-30 at 19:26 +0100, Chris Li wrote: >> >> The delta seems to be this line: >> ioatdma 0000:00:0f.0: ioat2_set_chainaddr: chainaddr: ffffe000 > > That's a reasonable address if the IOMMU is enabled. We start at 4GiB > and work down, so that's the second page given out (or the first 8KiB > chunk). > > It looks like the DMA is going AWOL causing the initialisation to > fail... but it's interesting that there are no DMA faults reported by > the IOMMU. > It seems the 5400 has a dedicated remapping engine just for the DMA device [1], is Linux only setting up the iommus per root port (which the DMA bypasses)?? From the dmesg: > IOMMU 0: reg_base_addr fe710000 ver 1:0 cap 900000c2f0462 ecap e01 > DMAR: DRHD base: 0x000000fe714000 flags: 0x0 > IOMMU 1: reg_base_addr fe714000 ver 1:0 cap 900000c2f0462 ecap e01 > DMAR: DRHD base: 0x000000fe719000 flags: 0x0 > IOMMU 2: reg_base_addr fe719000 ver 1:0 cap 900000c2f0462 ecap e01 > DMAR: DRHD base: 0x000000fe718000 flags: 0x1 > IOMMU 3: reg_base_addr fe718000 ver 1:0 cap 900000c2f0462 ecap e01 Where we expect bit 54 to be set for the DMA iommu, and it does not appear to show up. -- Dan [1]: http://www.intel.com/Assets/PDF/datasheet/318610.pdf (Section 3.11.2 page 256) -- 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/