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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 17DA2C433E2 for ; Tue, 1 Sep 2020 11:06:27 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 94EA6207BC for ; Tue, 1 Sep 2020 11:06:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 94EA6207BC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A18DE6B0003; Tue, 1 Sep 2020 07:06:25 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9C9336B0037; Tue, 1 Sep 2020 07:06:25 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 88F676B0055; Tue, 1 Sep 2020 07:06:25 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0078.hostedemail.com [216.40.44.78]) by kanga.kvack.org (Postfix) with ESMTP id 71EF86B0003 for ; Tue, 1 Sep 2020 07:06:25 -0400 (EDT) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 37D1F181AEF0B for ; Tue, 1 Sep 2020 11:06:25 +0000 (UTC) X-FDA: 77214213930.27.iron41_5c0005d27097 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin27.hostedemail.com (Postfix) with ESMTP id E993E3D669 for ; Tue, 1 Sep 2020 11:06:24 +0000 (UTC) X-HE-Tag: iron41_5c0005d27097 X-Filterd-Recvd-Size: 3424 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf32.hostedemail.com (Postfix) with ESMTP for ; Tue, 1 Sep 2020 11:06:24 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 508E268B05; Tue, 1 Sep 2020 13:06:18 +0200 (CEST) Date: Tue, 1 Sep 2020 13:06:17 +0200 From: Christoph Hellwig To: Tomasz Figa Cc: Christoph Hellwig , alsa-devel@alsa-project.org, linux-ia64@vger.kernel.org, Linux Doc Mailing List , nouveau@lists.freedesktop.org, linux-nvme@lists.infradead.org, linux-mips@vger.kernel.org, "James E.J. Bottomley" , linux-mm@kvack.org, linux-samsung-soc , Joonyoung Shim , linux-scsi@vger.kernel.org, Kyungmin Park , Ben Skeggs , Matt Porter , Linux Media Mailing List , Tom Lendacky , Pawel Osciak , Mauro Carvalho Chehab , "list@263.net:IOMMU DRIVERS , Joerg Roedel ," , Thomas Bogendoerfer , linux-parisc@vger.kernel.org, netdev@vger.kernel.org, Seung-Woo Kim , Linux Kernel Mailing List , "list@263.net:IOMMU DRIVERS , Joerg Roedel ," Subject: Re: [PATCH 05/28] media/v4l2: remove V4L2-FLAG-MEMORY-NON-CONSISTENT Message-ID: <20200901110617.GA13232@lst.de> References: <20200819065555.1802761-1-hch@lst.de> <20200819065555.1802761-6-hch@lst.de> <20200819135454.GA17098@lst.de> <20200820044347.GA4533@lst.de> <20200820052004.GA5305@lst.de> <20200820165407.GD12693@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-Rspamd-Queue-Id: E993E3D669 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Aug 20, 2020 at 07:33:48PM +0200, Tomasz Figa wrote: > > It wasn't meant to be too insulting, but I found this out when trying > > to figure out how to just disable it. But it also ends up using > > the actual dma attr flags for it's own consistency checks, so just > > not setting the flag did not turn out to work that easily. > > > > Yes, sadly the videobuf2 ended up becoming quite counterintuitive > after growing for the long years and that is reflected in the design > of this feature as well. I think we need to do something about it. So I'm about to respin the series and wonder how we should proceed. I've failed to come up with a clean patch to keep the flag and make it a no-op. Can you or your team give it a spin? Also I wonder if the flag should be renamed from NON_CONSISTENT to NON_COHERENT - the consistent thing is a weird wart from the times the old PCI DMA API that is mostly gone now.