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=-8.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 A1079C43387 for ; Mon, 14 Jan 2019 16:38:28 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 6C3E5206B7 for ; Mon, 14 Jan 2019 16:38:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="fKlHCVbH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6C3E5206B7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=2lT68hVX+hGNynx5TTMIalndhESJTlUh1iIaPrEFR7c=; b=fKlHCVbHW1+x0fPAgy6fDOva+ GbUtESeurxJJdpoWwDqN3+zWk5JJBQDvyZpBvbXLBv6CSiRRqf9mFjeIkOGUVjq2FdM8wGVUcg+ay puwqmSEtWmFfY6bZOCcKF8gTNjihZdfVqVQtz/UqeOv6J6eZosUHCaN41y2HOqWc8Ph193Z7T+wG0 kFK63u7Qvpx/Icto7qrpU+h+1ZArq4/VB7YGhMHvXsxQkzKQDsNntzzyxd5pzyam+l4xtI9WGZJEI 4JaADJKHbt1EXFF6ttrIdQvad9GnHGjqIgYrfdOOH6na+LPlax3JMNx1cD71Up+T53uS/vSb6dH0h lM5yfgHIA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gj5Fq-0004ie-UW; Mon, 14 Jan 2019 16:38:26 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gj5Fn-0004iI-Sg for linux-arm-kernel@lists.infradead.org; Mon, 14 Jan 2019 16:38:25 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8BEEEA78; Mon, 14 Jan 2019 08:38:23 -0800 (PST) Received: from [10.1.196.75] (e110467-lin.cambridge.arm.com [10.1.196.75]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E0FCD3F5BD; Mon, 14 Jan 2019 08:38:21 -0800 (PST) Subject: Re: [PATCH] Revert "ARM: dma-mapping: Set proper DMA ops in arm_iommu_detach_device()" To: Thierry Reding , Marek Szyprowski References: <20190114132240.12125-1-m.szyprowski@samsung.com> <20190114160902.GB9218@ulmo> From: Robin Murphy Message-ID: <4f7fd8db-33e4-9c8d-2fee-1ca9c98a9276@arm.com> Date: Mon, 14 Jan 2019 16:38:20 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20190114160902.GB9218@ulmo> Content-Language: en-GB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190114_083823_926226_C86FF3BB X-CRM114-Status: GOOD ( 19.50 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Bartlomiej Zolnierkiewicz , Russell King , linux-kernel@vger.kernel.org, Tobias Jakobi , iommu@lists.linux-foundation.org, Ben Skeggs , Christoph Hellwig , linux-arm-kernel@lists.infradead.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 14/01/2019 16:09, Thierry Reding wrote: > On Mon, Jan 14, 2019 at 02:22:40PM +0100, Marek Szyprowski wrote: >> This reverts commit 1874619a7df4b14b23b14877e705ae15325773e3. >> >> That patch broke IOMMU support for devices, which fails to probe for the >> first time and use deferred probe approach. When non-NULL dma_ops is set >> in arm_iommu_detach_device(), the given device later ignored by >> arch_setup_dma_ops() and stays with non-IOMMU dma_ops. >> >> Reported-by: Tobias Jakobi >> Fixes: 1874619a7df4 "ARM: dma-mapping: Set proper DMA ops in arm_iommu_detach_device()" >> Signed-off-by: Marek Szyprowski >> --- >> arch/arm/mm/dma-mapping.c | 12 ++++++------ >> 1 file changed, 6 insertions(+), 6 deletions(-) > > Can you point out exactly what drivers break because of this change? We > need to find a solution that works for everyone. Reverting is only > marginally useful because somebody will just end up wanting to revert > the revert because a different driver is now broken. At first glance, it sounds like what we really want is for arch_teardown_iommu_ops() to completely clear any ops that arch_setup_dma_ops() installed - does the below suffice? Robin. ----->8----- diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index f1e2922e447c..1e3e08a1c456 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -2390,4 +2390,6 @@ void arch_teardown_dma_ops(struct device *dev) return; arm_teardown_iommu_dma_ops(dev); + /* Let arch_setup_dma_ops() start again from scratch upon re-probe */ + set_dma_ops(dev, NULL); } _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel