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=-3.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 CF1ACC4646B for ; Wed, 26 Jun 2019 07:17:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A6BD9216F4 for ; Wed, 26 Jun 2019 07:17:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="OYdbHp6k" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726925AbfFZHR0 (ORCPT ); Wed, 26 Jun 2019 03:17:26 -0400 Received: from mail-wm1-f65.google.com ([209.85.128.65]:37290 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725876AbfFZHRZ (ORCPT ); Wed, 26 Jun 2019 03:17:25 -0400 Received: by mail-wm1-f65.google.com with SMTP id f17so899122wme.2; Wed, 26 Jun 2019 00:17:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=RERYcPC3soW1Vk8htH1oyJ3L3Gz0OePkhqi35k0/p0I=; b=OYdbHp6ktNPuS0z/WMYn7B2z7aZw5V6gZdgMOUxyCZTagqn4f5ClzVq4NELVY3G1qp Myo58k+xbuxDbfFrqJIHWc3nqEsQipwsUs1PjtNgFAqook+ApL8c6LLKaaYPs8bOCkJD BpQEEBVkE8HU1idCaM9tlTHsjEbdemWTB3qV5hqlHnpFuNWh3Xc2TN9zR2ulem/II+Jy NkNUls8ZHdL07Tb4HbhoCxPTApdB74/2KsD1LB5G8XqW7VvnqDv/45li3v1P3hg5PVFp fSZNP3HqKvGXM/uFLzFqcbr9659XfFLOdbgGzOwWn0h/KkzSnm46gfTi6r6acFtB+CUr tU6w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=RERYcPC3soW1Vk8htH1oyJ3L3Gz0OePkhqi35k0/p0I=; b=H3uFMGbpxBPjAOoQ/stzrJtEDlMUBTgtXTvLDXQ72ZUJ1iHbs43Q5JfN/nUAXbNhVu yS5OxGaGUEsX+iVNk27RFz2/w7Kb8rpPBeyigVbzayH7iAgw2qneWith3UgueFngWpER CDG0eDRC+buojszTuYTWEskH9b2JafltKCjzV3k+TabcMjKhXWs1GE45v9lw0BTndNVs YjWv4sY9dXgFoAfekZhF0pR4GmXTkpgdPMigGMjQcfLhQPJRvJs59hZdyt0hDRvd+8nb WGz9jbgIdQ/9edMKDuy4kkHwm6rZNZwzeqtnifXibp2a4cse1GzD6PgKd0/S4FnLZ5aQ Itzg== X-Gm-Message-State: APjAAAXJbds/PvcNw6864RQTX/+8Jqtsp/5DW+yOsN8E9Q589KOaWT8d SGrhjLml60lrz0LKzL5Qitjj9ESQGEmeZdPWgio= X-Google-Smtp-Source: APXvYqwU9UitzhmKJ5t/pfR8HxsTFi/sqtvSVbTXtdDxS2SooK3ATbTGPoFE8wuP0Gr+BGzKdjZRLixWxlUEFzSUG/Q= X-Received: by 2002:a7b:c313:: with SMTP id k19mr1470647wmj.2.1561533442305; Wed, 26 Jun 2019 00:17:22 -0700 (PDT) MIME-Version: 1.0 References: <20190625121321.10197-1-hch@lst.de> In-Reply-To: <20190625121321.10197-1-hch@lst.de> From: Manuel Lauss Date: Wed, 26 Jun 2019 09:16:46 +0200 Message-ID: Subject: Re: [PATCH] au1200fb: don't use DMA_ATTR_NON_CONSISTENT To: Christoph Hellwig Cc: Bartlomiej Zolnierkiewicz , Linux-MIPS , linux-fbdev , LKML Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 25, 2019 at 2:13 PM Christoph Hellwig wrote: > > au1200fb allocates DMA memory using DMA_ATTR_NON_CONSISTENT, but never > calls dma_cache_sync to synchronize the memory between the CPU and the > device. If it was use on a not cache coherent bus that would be fatal, > but as far as I can tell from the naming and the mips platform > implementation it always is used in cache coherent systems. Remove > the DMA_ATTR_NON_CONSISTENT flag, which is a no-op in that case. Very early au1200 chips, on which this driver apparently was developed on, had issues with cache coherency, but this was fixed in a later step, none of the 3 steppings I have access to exhibit any problems with this patch applied. > Signed-off-by: Christoph Hellwig Acked-By: Manuel Lauss