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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 66BE0CA9EA0 for ; Tue, 22 Oct 2019 23:48:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3C21E20700 for ; Tue, 22 Oct 2019 23:48:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389797AbfJVXsp (ORCPT ); Tue, 22 Oct 2019 19:48:45 -0400 Received: from mga07.intel.com ([134.134.136.100]:55767 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732393AbfJVXso (ORCPT ); Tue, 22 Oct 2019 19:48:44 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 22 Oct 2019 16:48:43 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,218,1569308400"; d="scan'208";a="399211273" Received: from srajamoh-mobl2.amr.corp.intel.com (HELO pbossart-mobl3.intel.com) ([10.251.20.203]) by fmsmga006.fm.intel.com with ESMTP; 22 Oct 2019 16:48:41 -0700 From: Pierre-Louis Bossart To: alsa-devel@alsa-project.org Cc: linux-kernel@vger.kernel.org, tiwai@suse.de, broonie@kernel.org, vkoul@kernel.org, gregkh@linuxfoundation.org, jank@cadence.com, srinivas.kandagatla@linaro.org, slawomir.blauciak@intel.com, Bard liao , Rander Wang , Ranjani Sridharan , Pierre-Louis Bossart Subject: [PATCH 0/3] soundwire: use UniqueID only when relevant Date: Tue, 22 Oct 2019 18:48:05 -0500 Message-Id: <20191022234808.17432-1-pierre-louis.bossart@linux.intel.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. 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(-) -- 2.20.1