Return-path: Received: from wf-out-1314.google.com ([209.85.200.171]:24636 "EHLO wf-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755498AbZCWRJq (ORCPT ); Mon, 23 Mar 2009 13:09:46 -0400 MIME-Version: 1.0 In-Reply-To: <43e72e890903161813q1e069891jb7c669a539e3ff7f@mail.gmail.com> References: <43e72e890903161215u343cbb19v6d6cbf36794e252a@mail.gmail.com> <20090317093445G.fujita.tomonori@lab.ntt.co.jp> <43e72e890903161813q1e069891jb7c669a539e3ff7f@mail.gmail.com> Date: Mon, 23 Mar 2009 10:09:28 -0700 Message-ID: <43e72e890903231009m6416f07brafe3088eae63abc5@mail.gmail.com> (sfid-20090323_180948_180331_9AEEC76D) Subject: Re: AMD Quad core - PCI-DMA: Out of IOMMU space on > 4 GB RAM From: "Luis R. Rodriguez" To: FUJITA Tomonori Cc: linux-wireless@vger.kernel.org, joerg.roedel@amd.com, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Mon, Mar 16, 2009 at 6:13 PM, Luis R. Rodriguez wrote: > On Mon, Mar 16, 2009 at 5:35 PM, FUJITA Tomonori > wrote: >> On Mon, 16 Mar 2009 12:15:37 -0700 >> "Luis R. Rodriguez" wrote: >> >>> I've run into "PCI-DMA: Out of IOMMU space" messages after loading and >>> unloading a module 30 times. The interesting thing is this only >>> happens if I have > 4 GB of memory. The box this occurs has AMD Phenom >>> quad core CPU so I take it a harware IOMMU is being used. Below are >>> example relevant messages with > 4 GB and then < 4 GB of memory. The >>> driver I tested this with was ath9k. It could be an issue perhaps with >>> ath9k but I am unable to find an issue in our probe/removal. >>> >>> Could this be an issue with the AMD IOMMU used? Or is it more likely a >>> driver issue? >> >> ath9k wants DMA_32BIT_MASK, right? If so, GART IOMMU does nothing on a >> system with < 4GB memory since ath9k can access to all the memory >> addresses directly. With >4GB memory, GART needs to remap an address >> higher than 4GB because ath9k wants DMA_32BIT_MASK. >> >> From a quick look, ath9k doesn't call pci_unmap_single for rx >> buffers. Though I might be wrong because I don't know anything about >> the driver. > > You seem to be right actually, we were calling pci_unmap_single() for > rx buffers on the RX tasklet but never for the simple case of removing > the module. Will test it out in a bit. That was it, thanks.. will propagate the patch. Luis