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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 34D11C388F9 for ; Fri, 23 Oct 2020 06:48:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CA0C9241A3 for ; Fri, 23 Oct 2020 06:48:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Tx5in8IS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S375428AbgJWGsi (ORCPT ); Fri, 23 Oct 2020 02:48:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42802 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S375419AbgJWGsh (ORCPT ); Fri, 23 Oct 2020 02:48:37 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 709D7C0613CE; Thu, 22 Oct 2020 23:48:37 -0700 (PDT) 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:To:From:Date:Sender:Reply-To:Cc: Content-Transfer-Encoding:Content-ID:Content-Description; bh=D9BSERH8ih1u+6l81BXwEfO3WbdwyDqTa0foZ95ppTs=; b=Tx5in8IS3ZrlOQR1hw4rSA2ItZ /EtjDvxk7ZQ4p7vDOinRhe9SCX6JstnBsBix456/AOjX8q9d6aIZ/SDs0MMTWPIt7hVmr6t8xAPZb GjcAbtIIqDtkWWHk1ma2q1E0ZeoZo+278v82AJ8CC9Qzmp8RCKv3hIvhpn5mTfemOgesu+qqsuOLQ Jwxaj85RBsyL2z0/vPWznuqpNAQNrgpf95kaIQ/TSmk2ZNoBZmk5CtuuoIgOLxVEqh7BLCSKgZSms g32q0VgMEMAETedrJ4nXop2B4UYhGdQmOwjE2apgCNizq6HILfk5Hw2BQ9c5C8ZRgEha3/BmPB8lO kRD4wbGw==; Received: from hch by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kVqsK-00065i-DT; Fri, 23 Oct 2020 06:48:32 +0000 Date: Fri, 23 Oct 2020 07:48:32 +0100 From: Christoph Hellwig To: Christoph Hellwig , Robin Murphy , Jonathan Marek , David Airlie , freedreno@lists.freedesktop.org, open list , "open list:DRM DRIVER FOR MSM ADRENO GPU" , iommu@lists.linux-foundation.org, "open list:DRM DRIVER FOR MSM ADRENO GPU" , Sean Paul Subject: Re: [PATCH 2/3] drm/msm: add DRM_MSM_GEM_SYNC_CACHE for non-coherent cache maintenance Message-ID: <20201023064832.GA23355@infradead.org> References: <20201005082914.GA31702@infradead.org> <3e0b91be-e4a4-4ea5-7d58-6e71b8d51932@marek.ca> <20201006072306.GA12834@infradead.org> <148a1660-f0fc-7163-2240-6b94725342b5@marek.ca> <20201007062519.GA23519@infradead.org> <20201015065532.GA15371@infradead.org> <20201015153334.GF438822@phenom.ffwll.local> <20201015154300.GA8047@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201015154300.GA8047@infradead.org> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 15, 2020 at 04:43:01PM +0100, Christoph Hellwig wrote: > > Somewhat related, but is there a way to tell the dma-api to fail instead > > of falling back to swiotlb? In many case for gpu drivers it's much better > > if we fall back to dma_alloc_coherent and manage the copying ourselves > > instead of abstracting this away in the dma-api. Currently that's "solved" > > rather pessimistically by always allocating from dma_alloc_coherent if > > swiotlb could be in the picture (at least for ttm based drivers, i915 just > > falls over). > > Is this for the alloc_pages plus manually map logic in various drivers? > > They should switch to the new dma_alloc_pages API that I'll send to > Linus for 5.10 soon. Daniel, can you clarify this?