From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752654AbbAGMOq (ORCPT ); Wed, 7 Jan 2015 07:14:46 -0500 Received: from smtprelay02.ispgateway.de ([80.67.18.14]:42852 "EHLO smtprelay02.ispgateway.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751783AbbAGMOn (ORCPT ); Wed, 7 Jan 2015 07:14:43 -0500 X-Greylist: delayed 332 seconds by postgrey-1.27 at vger.kernel.org; Wed, 07 Jan 2015 07:14:43 EST Message-ID: <54AD21E2.2020100@ladisch.de> Date: Wed, 07 Jan 2015 13:09:06 +0100 From: Clemens Ladisch User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: Raimonds Cicans , linux-kernel@vger.kernel.org Subject: Re: Questions about IOMMU & PCIe switch References: <54ACB0D4.3000008@apollo.lv> In-Reply-To: <54ACB0D4.3000008@apollo.lv> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Df-Sender: bGludXgta2VybmVsQGNsLmRvbWFpbmZhY3Rvcnkta3VuZGUuZGU= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Raimonds Cicans wrote: > We have two kinds of PCIe cards: > A1 - based on chip B > A2 - based on same chip B but behind PCIe switch > > Card A1 work flawlessly in any configuration, > but card A2 work flawlessly only if system > lack IOMMU or have disabled IOMMU In theory, such a switch should be transparent. > Do we have to treat card with PCIe switch in special way? No. But the switch has to work correctly, and driver must be written correctly. Which switch? Which driver? Regards, Clemens