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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham 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 2A028C10F12 for ; Wed, 17 Apr 2019 09:30:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F2A5D2073F for ; Wed, 17 Apr 2019 09:30:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731388AbfDQJaY (ORCPT ); Wed, 17 Apr 2019 05:30:24 -0400 Received: from smtp1.de.adit-jv.com ([93.241.18.167]:58737 "EHLO smtp1.de.adit-jv.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726237AbfDQJaY (ORCPT ); Wed, 17 Apr 2019 05:30:24 -0400 Received: from localhost (smtp1.de.adit-jv.com [127.0.0.1]) by smtp1.de.adit-jv.com (Postfix) with ESMTP id CE9663C00C0; Wed, 17 Apr 2019 11:30:21 +0200 (CEST) Received: from smtp1.de.adit-jv.com ([127.0.0.1]) by localhost (smtp1.de.adit-jv.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id wFI6WIyU5Sc3; Wed, 17 Apr 2019 11:30:15 +0200 (CEST) Received: from HI2EXCH01.adit-jv.com (hi2exch01.adit-jv.com [10.72.92.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by smtp1.de.adit-jv.com (Postfix) with ESMTPS id CC7D63C00DD; Wed, 17 Apr 2019 11:30:10 +0200 (CEST) Received: from [10.72.93.172] (10.72.93.172) by HI2EXCH01.adit-jv.com (10.72.92.24) with Microsoft SMTP Server (TLS) id 14.3.439.0; Wed, 17 Apr 2019 11:30:10 +0200 Subject: Re: [ALSA patch] [PATCH] ALSA: pcm: Enable MMAP status and control for ARMv7 and ARMv8 To: Takashi Iwai CC: , , , , References: <1555490771-13242-1-git-send-email-twischer@de.adit-jv.com> From: Timo Wischer Message-ID: <5946b2b4-ecf7-8266-2998-a19b7d9a2d2c@de.adit-jv.com> Date: Wed, 17 Apr 2019 11:30:10 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Originating-IP: [10.72.93.172] Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/17/19 11:21, Takashi Iwai wrote: > On Wed, 17 Apr 2019 10:46:11 +0200, > wrote: >> From: Timo Wischer >> >> Since ARMv7 hardware cache coherence is supported. >> "The SCU maintains coherency between the individual data caches in the >> Cortex-A5 MPCore processor using a variation of the MOESI protocol" [1]. >> >> Therefore this patch enables the MMAP access to the status and control >> structures. This avoids HWSYYNC ioctl calls and therefore lowers the CPU >> usage. >> >> [1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0434c/ >> BABJECBF.html > Interesting... I thought it would never work properly on ARM. > If it really works like that, I'd happily apply the change. > But I'd like to hear a confirmation from ARM people before merging > such an intensive change. Hi Takashi, do I need to send this patch to any other mailing list or do you think some corresponding guy is already on the lists I have used? > > > thanks, > > Takashi > >> Signed-off-by: Timo Wischer >> --- >> sound/core/pcm_native.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c >> index 1d84529..b8019ef 100644 >> --- a/sound/core/pcm_native.c >> +++ b/sound/core/pcm_native.c >> @@ -3225,7 +3225,8 @@ static __poll_t snd_pcm_poll(struct file *file, poll_table *wait) >> * Only on coherent architectures, we can mmap the status and the control records >> * for effcient data transfer. On others, we have to use HWSYNC ioctl... >> */ >> -#if defined(CONFIG_X86) || defined(CONFIG_PPC) || defined(CONFIG_ALPHA) >> +#if defined(CONFIG_X86) || defined(CONFIG_PPC) || defined(CONFIG_ALPHA) || \ >> + (defined(CONFIG_ARM) && defined(CONFIG_CPU_V7)) || defined(CONFIG_ARM64) >> /* >> * mmap status record >> */ >> -- >> 2.7.4 >> >> _______________________________________________ >> Patch mailing list >> Patch@alsa-project.org >> https://mailman.alsa-project.org/mailman/listinfo/patch >>