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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 25F7DC4363C for ; Wed, 7 Oct 2020 06:25:33 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (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 84D1620B1F for ; Wed, 7 Oct 2020 06:25:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="PNf5g862" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 84D1620B1F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id 0258D87258; Wed, 7 Oct 2020 06:25:32 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id n2JLUGROmSyD; Wed, 7 Oct 2020 06:25:31 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by hemlock.osuosl.org (Postfix) with ESMTP id 666A48721F; Wed, 7 Oct 2020 06:25:31 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 50C3BC016F; Wed, 7 Oct 2020 06:25:31 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id 73ECBC0051 for ; Wed, 7 Oct 2020 06:25:29 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id 672A122D0D for ; Wed, 7 Oct 2020 06:25:29 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id KsSzd08-zz-j for ; Wed, 7 Oct 2020 06:25:28 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by silver.osuosl.org (Postfix) with ESMTPS id 4590D22636 for ; Wed, 7 Oct 2020 06:25:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=hGY4fKBH3lXrbLnK7loOw4AUvRukRocZITr25lF2ycI=; b=PNf5g8627c2NOMQqhvL0eUPUY9 pG18AoTA0MELpyOL/b9ay/ykTBDatHDGS3jlfCwIic9g3kmcO8E6ny88Ao5zGscnjagnX/WHNFZM5 eZ2NTCUXNprEyCfiCQ/EGzyj6MxRlkn48EyhjY9cX/mqtGmGzUcF/05YoWWqOT3az/7lCzZyLl22/ JnPVX/l/zI1jAPk8897xZBq8Pfmxbi5IX6xg+uZiAsB6ckYTKIB56aoRVnPqszsGMjoVPJQUTNCy1 9FlS3lHhBHqvrySZFyfKyRFMIWGkyvr72addRKiyZPfjxgqJLXANCq04HlVz81s002Ig6I9P5Ekbx glO7NLFQ==; Received: from hch by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kQ2t5-0006Rp-Uy; Wed, 07 Oct 2020 06:25:19 +0000 Date: Wed, 7 Oct 2020 07:25:19 +0100 From: Christoph Hellwig To: Jonathan Marek Subject: Re: [PATCH 2/3] drm/msm: add DRM_MSM_GEM_SYNC_CACHE for non-coherent cache maintenance Message-ID: <20201007062519.GA23519@infradead.org> References: <20201001002709.21361-1-jonathan@marek.ca> <20201001002709.21361-3-jonathan@marek.ca> <20201002075321.GA7547@infradead.org> <20201005082914.GA31702@infradead.org> <3e0b91be-e4a4-4ea5-7d58-6e71b8d51932@marek.ca> <20201006072306.GA12834@infradead.org> <148a1660-f0fc-7163-2240-6b94725342b5@marek.ca> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <148a1660-f0fc-7163-2240-6b94725342b5@marek.ca> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Cc: David Airlie , freedreno@lists.freedesktop.org, open list , "open list:DRM DRIVER FOR MSM ADRENO GPU" , Christoph Hellwig , iommu@lists.linux-foundation.org, Daniel Vetter , "open list:DRM DRIVER FOR MSM ADRENO GPU" , Sean Paul , Robin Murphy X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 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 Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Tue, Oct 06, 2020 at 09:19:32AM -0400, Jonathan Marek wrote: > One example why drm/msm can't use DMA API is multiple page table support > (that is landing in 5.10), which is something that definitely couldn't work > with DMA API. > > Another one is being able to choose the address for mappings, which AFAIK > DMA API can't do (somewhat related to this: qcom hardware often has ranges > of allowed addresses, which the dma_mask mechanism fails to represent, what > I see is drivers using dma_mask as a "maximum address", and since addresses > are allocated from the top it generally works) That sounds like a good enough rason to use the IOMMU API. I just wanted to make sure this really makes sense. _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu