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=-0.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 EECDDC004C9 for ; Tue, 7 May 2019 14:43:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C465E20825 for ; Tue, 7 May 2019 14:43:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726803AbfEGOnR (ORCPT ); Tue, 7 May 2019 10:43:17 -0400 Received: from mga06.intel.com ([134.134.136.31]:34606 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726444AbfEGOnR (ORCPT ); Tue, 7 May 2019 10:43:17 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 07 May 2019 07:43:16 -0700 X-ExtLoop1: 1 Received: from asakoono-mobl.gar.corp.intel.com (HELO [10.251.159.132]) ([10.251.159.132]) by fmsmga005.fm.intel.com with ESMTP; 07 May 2019 07:43:15 -0700 Subject: Re: [PATCH 1/8] soundwire: intel: filter SoundWire controller device search To: Vinod Koul Cc: alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, tiwai@suse.de, broonie@kernel.org, gregkh@linuxfoundation.org, liam.r.girdwood@linux.intel.com, jank@cadence.com, joe@perches.com, srinivas.kandagatla@linaro.org, Sanyog Kale References: <20190504002926.28815-1-pierre-louis.bossart@linux.intel.com> <20190504002926.28815-2-pierre-louis.bossart@linux.intel.com> <20190507122651.GO16052@vkoul-mobl> From: Pierre-Louis Bossart Message-ID: <47fd3ca6-6910-f101-9b63-f653cd1443f9@linux.intel.com> Date: Tue, 7 May 2019 09:43:15 -0500 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: <20190507122651.GO16052@vkoul-mobl> 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 5/7/19 7:26 AM, Vinod Koul wrote: > On 03-05-19, 19:29, Pierre-Louis Bossart wrote: >> The convention is that the SoundWire controller device is a child of >> the HDAudio controller. However there can be more than one child >> exposed in the DSDT table, and the current namespace walk returns the >> last device. >> >> Add a filter and terminate early when a valid _ADR is provided, >> otherwise keep iterating to find the next child. > > So what are the other devices in DSDT here.. this is what I see: Scope (HDAS) { Device (IDA) { Name (_ADR, 0x00020001) // _ADR: Address } } I thought this was nonsense but your question triggered me to look into the Intel SST ACPI specs (not public I am afraid but shared with the OS who shall not be named). Using the same source of information as below, I *believe* this is HDaudio related, bits 31..16 mean HDaudio with codec SDI 2, and NodeId 1 for the function group. This would make sense as I believe there are two codecs on the board that can be pin-strapped to boot either in HDaudio or SoundWire mode- but this is a conjecture only. At any rate, we need a hardware rework and mutual exclusion between HDaudio and SoundWire, so we have to ignore this one when SoundWire is enabled. >> + >> + /* >> + * On some Intel platforms, multiple children of the HDAS >> + * device can be found, but only one of them is the SoundWire >> + * controller. The SNDW device is always exposed with >> + * Name(_ADR, 0x40000000) so filter accordingly >> + */ >> + if (adr != 0x40000000) > > I do not recall if 4 corresponds to the links you have or soundwire > device type, is this number documented somewhere is HDA specs? I thought it was a magic number, but I did check and for once it's documented and the values match the spec :-) I see in the ACPI docs bits 31..28 set to 4 indicate a SoundWire Link Type and bits 3..0 indicate the SoundWire controller instance, the rest is reserved to zero. > > Also it might good to create a define for this I will respin this one to add the documentation above, and only filter on the 4 ms-bits. Thanks for forcing me to RTFM :-)