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=-2.2 required=3.0 tests=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 7FC9BC5DF64 for ; Wed, 6 Nov 2019 19:30:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5D55E21882 for ; Wed, 6 Nov 2019 19:30:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730949AbfKFTa3 (ORCPT ); Wed, 6 Nov 2019 14:30:29 -0500 Received: from mga17.intel.com ([192.55.52.151]:12634 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727681AbfKFTa3 (ORCPT ); Wed, 6 Nov 2019 14:30:29 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 06 Nov 2019 11:30:28 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,275,1569308400"; d="scan'208";a="205931904" Received: from rbidasar-mobl.amr.corp.intel.com (HELO [10.251.0.251]) ([10.251.0.251]) by orsmga006.jf.intel.com with ESMTP; 06 Nov 2019 11:30:27 -0800 Subject: Re: [alsa-devel] [PATCH 0/3] soundwire: use UniqueID only when relevant To: alsa-devel@alsa-project.org Cc: tiwai@suse.de, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, Ranjani Sridharan , vkoul@kernel.org, broonie@kernel.org, srinivas.kandagatla@linaro.org, jank@cadence.com, slawomir.blauciak@intel.com, Bard liao , Rander Wang References: <20191022234808.17432-1-pierre-louis.bossart@linux.intel.com> From: Pierre-Louis Bossart Message-ID: Date: Wed, 6 Nov 2019 13:30:27 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: <20191022234808.17432-1-pierre-louis.bossart@linux.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 10/22/19 6:48 PM, Pierre-Louis Bossart wrote: > The hardware UniqueID, typically enabled with pin-strapping, is > required during enumeration to avoid conflicts between devices of the > same type. > > When there are no devices of the same type, using the UniqueID is > overkill and results in a lot of probe errors due to mismatches > between ACPI tables and hardware capabilities. For example it's not > uncommon for BIOS vendors to copy/paste the same settings between > platforms but the hardware pin-strapping is different. This is > perfectly legit and permitted by MIPI specs. > > With this patchset, the UniqueID is only used when multiple devices of > the same type are detected. The loop to detect multiple identical > devices is not super efficient but with typically fewer than 4 devices > per link there's no real incentive to be smarter. > > This change is only implemented for ACPI platforms, for DeviceTree > there is no change. Vinod, this series has been submitted for review on October 22 and I answered to your questions. There's been no feedback since October 24, so is there any sustained objection here? ACPI platforms are completely unmanageable without this patchset. > > Pierre-Louis Bossart (3): > soundwire: remove bitfield for unique_id, use u8 > soundwire: slave: add helper to extract slave ID > soundwire: ignore uniqueID when irrelevant > > drivers/soundwire/bus.c | 7 +-- > drivers/soundwire/slave.c | 98 +++++++++++++++++++++++++++-------- > include/linux/soundwire/sdw.h | 4 +- > 3 files changed, 84 insertions(+), 25 deletions(-) >