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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 A2534C5519A for ; Mon, 27 Apr 2020 12:48:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8312720663 for ; Mon, 27 Apr 2020 12:48:48 +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="HjDhTg1L" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727068AbgD0Msp (ORCPT ); Mon, 27 Apr 2020 08:48:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46652 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726728AbgD0Mso (ORCPT ); Mon, 27 Apr 2020 08:48:44 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D00FEC0610D5; Mon, 27 Apr 2020 05:48:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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=BKTNTPqPREcmXGT5PW5iYYT+ca/npyb86/7EpHWqKOI=; b=HjDhTg1L1OtdVen2udkp2y9E+U aKGOIau3zpYJQaUzLVXoerYxehlPLp4vqyeHkHqrzwBI/fz0Z91RgJUB8OCGAAA+xC4PTaEj5UL8+ M2EXA8P5hmIeeZZE1pZyfl/xpIIBwe2ygUV2Jc9ymVDb5tpEVyeISjqQEAHcP5VByue/xqLR8oX6B PS/SnPaB72CwbGUlsRdtkKs+QUaoavtKt/nvFAkqSGzj4ke6Quc1ao+DfXwrtFebUt/vyBVofuvpr JCbBdHCxyx6FP7XIMfq4Z1jZ+lkFTUwoGK515dhxpjoXVW5YyoPxYtdW2jFF5K4sxM1037q6YodDG DwSwAlGg==; Received: from hch by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jT3Bg-0008CA-Ju; Mon, 27 Apr 2020 12:48:40 +0000 Date: Mon, 27 Apr 2020 05:48:40 -0700 From: Christoph Hellwig To: Tomasz Figa Cc: Christoph Hellwig , Catalin Marinas , Will Deacon , Nicolas Boichat , Shik Chen , Linux Media Mailing List , notify@kernel.org, Keiichi Watanabe , Ricky Liang , Mauro Carvalho Chehab , Laurent Pinchart , lkml , Kieran Bingham , Vlastimil Babka , Christoph Lameter , Sergey Senozhatsky Subject: Re: [PATCH] media: uvcvideo: Use streaming DMA APIs to transfer buffers Message-ID: <20200427124840.GA30327@infradead.org> References: <20190802131226.123800-1-shik@chromium.org> <20190930082310.GA1750@infradead.org> <20191001063744.GA10402@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Tue, Apr 21, 2020 at 01:21:15PM +0200, Tomasz Figa wrote: > On Thu, Feb 27, 2020 at 7:28 AM Tomasz Figa wrote: > > > > +Sergey Senozhatsky who's going to be looking into this. > > > > Hi Christoph, > > > > That said, I noticed that you also put a lot of effort into making the > > NONCONSISTENT attribute more usable. Perhaps that's the way to go here > > then? Of course we would need to make sure that the attribute is > > handled properly on ARM and ARM64, which are the most affected > > platforms. Right now neither handles them. The former doesn't use the > > generic DMA mapping ops, while the latter does, but doesn't enable a > > Kconfig option needed to allow generic inconsistent allocations. > > > > Any hints would be appreciated. > > Hi Christoph, would you have some time to check the above? > > Hi Catalin, Will, do you know why CONFIG_DMA_NONCOHERENT_CACHE_SYNC is > not enabled on arm64? NONCONSISTENT is still a mess, mostly because dma_cache_sync is such a horrible API. I've been wanting to switch to the normal sync_for_device / sync_for_cpu primitives instead. Let me see if I can expedite that.