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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 80EEAEB64DA for ; Wed, 5 Jul 2023 14:45:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232683AbjGEOpS (ORCPT ); Wed, 5 Jul 2023 10:45:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51464 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232663AbjGEOpG (ORCPT ); Wed, 5 Jul 2023 10:45:06 -0400 Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F0A871BDF; Wed, 5 Jul 2023 07:45:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1688568301; x=1720104301; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=s0GWJM5gFoud1+XZjR2N78Pc/ZDBarybll1Oke7Rovs=; b=kXRzAr1DMUkOspd90Mgaw5wg5aYYmRZ3NCAEXjxc2yJ1oWF8db5hmXJq i1jfWVI357igoyL7ew5GZ+wdtfPZ+Z5n8THbkfkCANl5uxuvfHHeku2PB O3GfkwK3QbKbqwyrFqKwXza1X03wbNt8Kt9BrtsMr/+MvbkWQSuuUYa8o b3wi41MohGnHsfDjJE2CP/qzHWq9cY1uD2bgVhCSB0KyU3UdgWgGPL2nD spAuYjLoIJZHYixzwo5LCWngzkn9YcznCYNXcb0JtXPLy4ErymORtKpwE WaOXvaDyZchgXy5ACtFBqkiEfrx+Ufs3q8NBLRrFakWcWd0pRuWcTwe6a w==; X-IronPort-AV: E=McAfee;i="6600,9927,10762"; a="362226707" X-IronPort-AV: E=Sophos;i="6.01,183,1684825200"; d="scan'208";a="362226707" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Jul 2023 07:45:01 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10762"; a="722430589" X-IronPort-AV: E=Sophos;i="6.01,183,1684825200"; d="scan'208";a="722430589" Received: from meggieha-mobl.ger.corp.intel.com (HELO [10.252.48.235]) ([10.252.48.235]) by fmsmga007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Jul 2023 07:44:57 -0700 Message-ID: <14395e2a-db0b-8f26-3356-741945478eb0@linux.intel.com> Date: Wed, 5 Jul 2023 16:44:55 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0 Thunderbird/102.11.0 Subject: Re: [PATCH 1/8] soundwire: fix enumeration completion Content-Language: en-US To: Johan Hovold Cc: Johan Hovold , Mark Brown , Vinod Koul , Bard Liao , Sanyog Kale , Srinivas Kandagatla , Banajit Goswami , Liam Girdwood , Jaroslav Kysela , Takashi Iwai , alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Rander Wang References: <20230705123018.30903-1-johan+linaro@kernel.org> <20230705123018.30903-2-johan+linaro@kernel.org> <907ad7a3-3384-c0c4-90a9-5beab4cc45e0@linux.intel.com> From: Pierre-Louis Bossart In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/5/23 16:30, Johan Hovold wrote: > On Wed, Jul 05, 2023 at 02:53:17PM +0200, Pierre-Louis Bossart wrote: >> On 7/5/23 14:30, Johan Hovold wrote: >>> The soundwire subsystem uses two completion structures that allow >>> drivers to wait for soundwire device to become enumerated on the bus and >>> initialised by their drivers, respectively. >>> >>> The code implementing the signalling is currently broken as it does not >>> signal all current and future waiters and also uses the wrong >>> reinitialisation function, which can potentially lead to memory >>> corruption if there are still waiters on the queue. >> >> That change sounds good, but I am not following the two paragraphs below. >> >>> Not signalling future waiters specifically breaks sound card probe >>> deferrals as codec drivers can not tell that the soundwire device is >>> already attached when being reprobed. >> >> What makes you say that? There is a test in the probe and the codec >> driver will absolutely be notified, see bus_type.c >> >> if (drv->ops && drv->ops->update_status) { >> ret = drv->ops->update_status(slave, slave->status); >> if (ret < 0) >> dev_warn(dev, "%s: update_status failed with status %d\n", __func__, >> ret); >> } > > I'm talking about signalling the codec driver using the soundwire device > via the completion structs. Unless the underling device is detached and > reattached, trying to wait for completion a second time will currently > timeout instead of returning immediately. > > This affects codecs like rt5682, which wait for completion in component > probe (see rt5682_probe()). > >>> Some codec runtime PM >>> implementations suffer from similar problems as waiting for enumeration >>> during resume can also timeout despite the device already having been >>> enumerated. >> >> I am not following this either. Are you saying the wait_for_completion() >> times out because of the init_completion/reinit_completion confusion, or >> something else. > > It times out because the completion counter is not saturated unless you > use complete_all(). > > Drivers that wait unconditionally in resume, will time out the second > time they are runtime resumed unless the underlying device has been > detached and reattached in the meantime (e.g. wsa881x_runtime_resume()). Makes sense. The default on Intel platforms is to reset the bus in all resume cases, that forces the attachment so we never saw the issue. For this patch: Reviewed-by: Pierre-Louis Bossart