From mboxrd@z Thu Jan 1 00:00:00 1970 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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 575CFC31E46 for ; Wed, 12 Jun 2019 12:09:03 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3484220866 for ; Wed, 12 Jun 2019 12:09:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3484220866 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id BC3C31B58; Wed, 12 Jun 2019 12:09:02 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 020051B51 for ; Wed, 12 Jun 2019 12:07:23 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from newverein.lst.de (verein.lst.de [213.95.11.211]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 9892379 for ; Wed, 12 Jun 2019 12:07:22 +0000 (UTC) Received: by newverein.lst.de (Postfix, from userid 2407) id 4822868B02; Wed, 12 Jun 2019 14:06:54 +0200 (CEST) Date: Wed, 12 Jun 2019 14:06:53 +0200 From: Christoph Hellwig To: Oliver Neukum Subject: Re: How to resolve an issue in swiotlb environment? Message-ID: <20190612120653.GA25285@lst.de> References: <20190611064158.GA20601@lst.de> <20190612073059.GA20086@lst.de> <1560339966.9728.18.camel@suse.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1560339966.9728.18.camel@suse.com> User-Agent: Mutt/1.5.17 (2007-11-01) Cc: Linux-Renesas , "linux-usb@vger.kernel.org" , "linux-block@vger.kernel.org" , "iommu@lists.linux-foundation.org" , Alan Stern , Christoph Hellwig X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org On Wed, Jun 12, 2019 at 01:46:06PM +0200, Oliver Neukum wrote: > > Thay is someething the virt_boundary prevents. But could still give > > you something like: > > > > 1536 4096 4096 1024 > > > > or > > 1536 16384 8192 4096 16384 512 > > That would kill the driver, if maxpacket were 1024. > > USB has really two kinds of requirements > > 1. What comes from the protocol > 2. What comes from the HCD > > The protocol wants just multiples of maxpacket. XHCI can satisfy > that in arbitrary scatter/gather. Other HCs cannot. We have no real way to enforce that for the other HCs unfortunately. I can't really think of any better way to handle their limitations except for setting max_segments to 1 or bounce buffering. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu