From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753143Ab0L1Xvq (ORCPT ); Tue, 28 Dec 2010 18:51:46 -0500 Received: from smtprelay03.ispgateway.de ([80.67.29.7]:46720 "EHLO smtprelay03.ispgateway.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752862Ab0L1Xvp (ORCPT ); Tue, 28 Dec 2010 18:51:45 -0500 X-Greylist: delayed 486 seconds by postgrey-1.27 at vger.kernel.org; Tue, 28 Dec 2010 18:51:44 EST Message-ID: <4D1A7628.3050704@steffen-moser.de> Date: Wed, 29 Dec 2010 00:43:36 +0100 From: Steffen Moser User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.9.2.12) Gecko/20101027 Thunderbird/3.1.6 MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: IOMMU and DMA mode of pata_jmicron Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit X-Df-Sender: lists@steffen-moser.de Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi all, I've encountered a problem with my AMD 890FX based system and linux-2.6.35.10 (x86_64 platform). After activating the option "IOMMU" in the mainboard's BIOS setup, the onboard P-ATA controller "JMicron Technology Corp. JMB361 AHCI/IDE (rev 02)" puts itself back in the PIO mode. When loading the module, the kernel reports: pata_jmicron 0000:06:00.1: BMDMA: failed to set dma mask, \ falling back to PIO This results, as expected, in a much too low data throughput between the system and the optical drives connected to the P-ATA controller. As soon as I deactivate IOMMU in BIOS setup, the P-ATA channel runs in the DMA mode again. The S-ATA controllers don't seem to be affected. My question is: Is this a known behavior? Are there any things I have to consider when activating IOMMU (which seems to be AMD-Vi) on an 890FX based system? Is it a problem of the chipset and/or the controller or is it related to a problem in the libata area? Some information about the affected system: - Mainboard: ASUS M4A89TD Pro/USB3 - BIOS version: 1101 (most recent version) - Chipset: AMD 890FX - Processor: AMD Phenom 1090T - Memory: 4 x 4 GB (Kingston KVR1333D3E9S/4G) - Distribution: openSUSE 11.3 - Kernel: 2.6.35.10 (from "kernel.org"), x86_64 Earlier versions of 2.6.35.x are affected, too. I haven't tested other kernel versions besides 2.6.35.x, yet. If you need further information (log files, information from "/proc", lspci, and so on), please let me know. Thank you very much in advance for any hint! Best regards, Steffen