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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 59BF0C2BA19 for ; Tue, 14 Apr 2020 09:00:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3FADF2074D for ; Tue, 14 Apr 2020 09:00:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2437301AbgDNJAG (ORCPT ); Tue, 14 Apr 2020 05:00:06 -0400 Received: from mga17.intel.com ([192.55.52.151]:58091 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2437280AbgDNI7z (ORCPT ); Tue, 14 Apr 2020 04:59:55 -0400 IronPort-SDR: OWTwU1xjVLqcg4ZyAc2E8iauy2D8NQFFAgIh3Qtx/WjYin6vwrODWfG+c/kipqDgoUZ1FWqSd3 TVk/LWTcP/2w== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Apr 2020 01:59:54 -0700 IronPort-SDR: nTRY4F9FYKyL9PfVM6xsZ5/9u0TRKVZNswM5DrPWZ0E9d8IIUx3Jnr5XWmaDCrn73Jj4aa20Gd 101o5HYFttVQ== X-IronPort-AV: E=Sophos;i="5.72,382,1580803200"; d="scan'208";a="253141691" Received: from aslawinx-mobl1.ger.corp.intel.com (HELO [10.249.141.95]) ([10.249.141.95]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Apr 2020 01:59:50 -0700 Subject: Re: [PATCH] ASoC: Intel: sst: ipc command timeout To: Brent Lu , alsa-devel@alsa-project.org Cc: Kate Stewart , Cezary Rojewski , linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Greg Kroah-Hartman , Takashi Iwai , Jie Yang , Pierre-Louis Bossart , Liam Girdwood , Richard Fontana , Mark Brown , Thomas Gleixner , Allison Randal References: <1586506705-3194-1-git-send-email-brent.lu@intel.com> From: =?UTF-8?Q?Amadeusz_S=c5=82awi=c5=84ski?= Message-ID: Date: Tue, 14 Apr 2020 10:59:47 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <1586506705-3194-1-git-send-email-brent.lu@intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/10/2020 10:18 AM, Brent Lu wrote: > After sending an ipc command to DSP, the host waits for the reply message > which will be read from SST_IPCD register in sst_byt_irq_thread() to > complete the transaction. Sometimes the value read from SST_IPCD register > is still the reply message for previous command instead of the waiting > command so ipc command timeout happens. > > In an experiment we read the same SST_IPCD register again when the defect > happens and found the value of second read is different from previous one > and is the correct reply message. It suggests the DSP is okay but the way > we read the register may be the cause. > > Currently the driver is using memcpy_fromio() to read the value of 64-bit > registers. This function is based on __builtin_memcpy() call and depends > on the implementation of compiler. Since this issue happens right after > the toolchain switched from clang 10 to clang 11, we replace the register > read with two readl() function calls to avoid all optimization from > compiler's library. > > Signed-off-by: Brent Lu > --- > sound/soc/intel/common/sst-dsp.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/sound/soc/intel/common/sst-dsp.c b/sound/soc/intel/common/sst-dsp.c > index ec66be2..12af7aa 100644 > --- a/sound/soc/intel/common/sst-dsp.c > +++ b/sound/soc/intel/common/sst-dsp.c > @@ -42,7 +42,7 @@ u64 sst_shim32_read64(void __iomem *addr, u32 offset) > { > u64 val; > > - memcpy_fromio(&val, addr + offset, sizeof(val)); > + sst_memcpy_fromio_32(NULL, &val, addr + offset, sizeof(val)); > return val; > } > EXPORT_SYMBOL_GPL(sst_shim32_read64); > I'm not convinced that it is a correct fix. From your description it seems to be a timing issue and you are just masking a problem, while real problem is flow which allows to read data before confirming that DSP finished processing.