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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 840AFC11D0C for ; Thu, 20 Feb 2020 19:58:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5B5E5206EF for ; Thu, 20 Feb 2020 19:58:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ti.com header.i=@ti.com header.b="DTsCqBR8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729036AbgBTT6p (ORCPT ); Thu, 20 Feb 2020 14:58:45 -0500 Received: from lelv0142.ext.ti.com ([198.47.23.249]:33792 "EHLO lelv0142.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728556AbgBTT6p (ORCPT ); Thu, 20 Feb 2020 14:58:45 -0500 Received: from lelv0265.itg.ti.com ([10.180.67.224]) by lelv0142.ext.ti.com (8.15.2/8.15.2) with ESMTP id 01KJw089091321; Thu, 20 Feb 2020 13:58:00 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1582228680; bh=QY2p35jnOX+tGMplVPO4s4YGc5syAWgGNS1/5A3DBp4=; h=Subject:To:CC:References:From:Date:In-Reply-To; b=DTsCqBR8FtIjnpDh/l+lhfbk3Uaf2ZuGIQnnwepawTxhnlRLQq/vwMf2gSXIm+su6 DcCUfK5eEA5uhGD2WpPt4Sz/JAxEGpqiSkTm/VMQlFlVtPpuoSBlp9yw7s12F8QlWh NNtp49MsOZXo3kpznuKug7aTIpSh+ypPWf5h1ypA= Received: from DLEE115.ent.ti.com (dlee115.ent.ti.com [157.170.170.26]) by lelv0265.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 01KJw0NP012754 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 20 Feb 2020 13:58:00 -0600 Received: from DLEE110.ent.ti.com (157.170.170.21) by DLEE115.ent.ti.com (157.170.170.26) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1847.3; Thu, 20 Feb 2020 13:58:00 -0600 Received: from lelv0326.itg.ti.com (10.180.67.84) by DLEE110.ent.ti.com (157.170.170.21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1847.3 via Frontend Transport; Thu, 20 Feb 2020 13:58:00 -0600 Received: from [128.247.59.107] (ileax41-snat.itg.ti.com [10.172.224.153]) by lelv0326.itg.ti.com (8.15.2/8.15.2) with ESMTP id 01KJw0q5053040; Thu, 20 Feb 2020 13:58:00 -0600 Subject: Re: [PATCH] ASoC: tas2562: Add support for digital volume control To: Mark Brown CC: , , , , References: <20200220172721.10547-1-dmurphy@ti.com> <20200220184507.GF3926@sirena.org.uk> <20200220191803.GH3926@sirena.org.uk> <6f3ff810-5e75-cb33-10d6-198a7c5cd202@ti.com> <20200220194048.GI3926@sirena.org.uk> From: Dan Murphy Message-ID: <7e08798f-ec91-1eb2-c082-cfbccc6d6202@ti.com> Date: Thu, 20 Feb 2020 13:52:55 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200220194048.GI3926@sirena.org.uk> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Mark On 2/20/20 1:40 PM, Mark Brown wrote: > On Thu, Feb 20, 2020 at 01:22:34PM -0600, Dan Murphy wrote: >> On 2/20/20 1:18 PM, Mark Brown wrote: >>> decisions causing changes in the driver. The system may have an >>> external amplifier they prefer to use for hardware volume control, may >>> prefer to do entirely soft volume control in their sound server or >>> something like that. >> But this is an amplifier.  Not sure why the system designer would design >> cascading amplifiers. >> And if that was the case wouldn't you want the output to be low so you don't >> overdrive the ext amplifier front end? > The point is that we don't know what people are doing and should try to > keep the kernel out of policy decisions unless there's something that's > clearly just unconditionaly right for all systems. It's a lot easier to > just have a clear rule that we defer to the wisdom of the silicon vendor > than try to get into defaults, and it's a lot easier to just do this as > consistently as we can rather than debating individual configuration > changes. > I completely agree on keeping policy decisions out of the kernel. >> I was considering safety in that the device is on at full blast (not sure >> why the HW is defaulted that way but it is). > I bet there's been issues with people turning things on and not > realising they need register writes to hear anything, and the volume > control here is a bit complex as well. Ack > >> But if volume is adjusted prior to playback then this is not an issue.  But >> if volume is not adjusted then it plays full blast. > Wouldn't be the first time. See all the dual purpose headphone/line > outputs that people build, sensible defaults for headphones and line > outputs are rather different. OK.  I will remove them. Will do v3 tomorrow as v2 rearranged the values properly.  V3 will remove them. Dan