From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=7h8a=CK=vger.kernel.org=linux-samsung-soc-owner@kernel.org>
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 346D5C433E6
	for <linux-samsung-soc@archiver.kernel.org>; Tue,  1 Sep 2020 14:57:45 +0000 (UTC)
Received: from vger.kernel.org (vger.kernel.org [23.128.96.18])
	by mail.kernel.org (Postfix) with ESMTP id 1BAAB206EB
	for <linux-samsung-soc@archiver.kernel.org>; Tue,  1 Sep 2020 14:57:45 +0000 (UTC)
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1726871AbgIALZC (ORCPT
        <rfc822;linux-samsung-soc@archiver.kernel.org>);
        Tue, 1 Sep 2020 07:25:02 -0400
Received: from verein.lst.de ([213.95.11.211]:53056 "EHLO verein.lst.de"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1726107AbgIALYH (ORCPT
        <rfc822;linux-samsung-soc@vger.kernel.org>);
        Tue, 1 Sep 2020 07:24:07 -0400
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 <hch@lst.de>
To:     Tomasz Figa <tfiga@chromium.org>
Cc:     Christoph Hellwig <hch@lst.de>, alsa-devel@alsa-project.org,
        linux-ia64@vger.kernel.org,
        Linux Doc Mailing List <linux-doc@vger.kernel.org>,
        nouveau@lists.freedesktop.org, linux-nvme@lists.infradead.org,
        linux-mips@vger.kernel.org,
        "James E.J. Bottomley" <James.Bottomley@hansenpartnership.com>,
        linux-mm@kvack.org,
        linux-samsung-soc <linux-samsung-soc@vger.kernel.org>,
        Joonyoung Shim <jy0922.shim@samsung.com>,
        linux-scsi@vger.kernel.org,
        Kyungmin Park <kyungmin.park@samsung.com>,
        Ben Skeggs <bskeggs@redhat.com>,
        Matt Porter <mporter@kernel.crashing.org>,
        Linux Media Mailing List <linux-media@vger.kernel.org>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Pawel Osciak <pawel@osciak.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        "list@263.net:IOMMU DRIVERS <iommu@lists.linux-foundation.org>, Joerg
        Roedel <joro@8bytes.org>," <linux-arm-kernel@lists.infradead.org>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        linux-parisc@vger.kernel.org, netdev@vger.kernel.org,
        Seung-Woo Kim <sw0312.kim@samsung.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "list@263.net:IOMMU DRIVERS <iommu@lists.linux-foundation.org>, Joerg
        Roedel <joro@8bytes.org>," <iommu@lists.linux-foundation.org>
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> <CAAFQd5COLxjydDYrfx47ht8tj-aNPiaVnC+WyQA7nvpW4gs=ww@mail.gmail.com> <20200819135454.GA17098@lst.de> <CAAFQd5BuXP7t3d-Rwft85j=KTyXq7y4s24mQxLr=VoY9krEGZw@mail.gmail.com> <20200820044347.GA4533@lst.de> <20200820052004.GA5305@lst.de> <CAAFQd5CFiA2WBaaPQ9ezvMjYZfNw37c42UEy9Pk7kJyCi1mLzQ@mail.gmail.com> <20200820165407.GD12693@lst.de> <CAAFQd5D=NzgjosB51-O_cH27a8V6CPgCfaPSfHHz7nKJPbazgg@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAAFQd5D=NzgjosB51-O_cH27a8V6CPgCfaPSfHHz7nKJPbazgg@mail.gmail.com>
User-Agent: Mutt/1.5.17 (2007-11-01)
Sender: linux-samsung-soc-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-samsung-soc.vger.kernel.org>
X-Mailing-List: linux-samsung-soc@vger.kernel.org

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.