Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C53ACC43381 for ; Tue, 26 Feb 2019 11:24:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A1783206B8 for ; Tue, 26 Feb 2019 11:24:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727662AbfBZLYN (ORCPT ); Tue, 26 Feb 2019 06:24:13 -0500 Received: from mx1.redhat.com ([209.132.183.28]:42258 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726240AbfBZLYM (ORCPT ); Tue, 26 Feb 2019 06:24:12 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 585AE368D0; Tue, 26 Feb 2019 11:24:12 +0000 (UTC) Received: from localhost (unknown [10.40.205.183]) by smtp.corp.redhat.com (Postfix) with ESMTP id D5BFA5DA2A; Tue, 26 Feb 2019 11:24:09 +0000 (UTC) Date: Tue, 26 Feb 2019 12:24:08 +0100 From: Stanislaw Gruszka To: Joerg Roedel Cc: Lorenzo Bianconi , Rosen Penev , linux-wireless , Samuel Sieb , Alexander Duyck , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: MT76x2U crashes XHCI driver on AMD Ryzen system Message-ID: <20190226112407.GB2989@redhat.com> References: <1547404075.1582.0@smtp.gmail.com> <20190114091841.GA23045@localhost.localdomain> <20190115090400.GA2267@localhost.localdomain> <20190218143742.GA11872@redhat.com> <20190226100535.GA20740@8bytes.org> <20190226103450.GA2989@redhat.com> <20190226104413.GH20740@8bytes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190226104413.GH20740@8bytes.org> User-Agent: Mutt/1.8.3 (2017-05-23) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Tue, 26 Feb 2019 11:24:12 +0000 (UTC) Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org On Tue, Feb 26, 2019 at 11:44:13AM +0100, Joerg Roedel wrote: > On Tue, Feb 26, 2019 at 11:34:51AM +0100, Stanislaw Gruszka wrote: > > On Tue, Feb 26, 2019 at 11:05:36AM +0100, Joerg Roedel wrote: > > If sg->offset > PAGE_SIZE is fine then most likely we have problem with > > alignment. > > The map_sg implementation in the AMD IOMMU driver uses sg_phys() which > handles the sg->page + sg->offset calculation fine. > > > Note hat issue is with dma_map_sg(), switching to dma_map_single() > > by using urb->transfer_buffer instead of urb->sg make things work > > on AMD IOMMU. > > On the other hand this points to a bug in the driver, I'll look further > if I can spot something there. I think so too. And I have done some changes that avoid strange allocation scheme and use usb synchronous messages instead of allocating buffers with unaligned sizes. However things work ok on Intel IOMMU and there is no documentation what are dma_map_sg() requirement versus dma_map_single() which works. I think there are some unwritten requirements and things can work on some platforms and fails on others (different IOMMUs, no-IOMMU on some ARCHes) Stanislaw