From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out1-smtp.messagingengine.com ([66.111.4.25]:32883 "EHLO out1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752141AbeBFJ20 (ORCPT ); Tue, 6 Feb 2018 04:28:26 -0500 Date: Tue, 6 Feb 2018 01:28:23 -0800 From: Greg KH To: Sasha Levin Cc: Mark Brown , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" , Abhijeet Kumar Subject: Re: [PATCH AUTOSEL for 4.14 029/110] ASoC: nau8825: fix issue that pop noise when start capture Message-ID: <20180206092823.GA31558@kroah.com> References: <20180203180015.29073-1-alexander.levin@microsoft.com> <20180203180015.29073-29-alexander.levin@microsoft.com> <20180205114154.GB12384@sirena.org.uk> <20180206014120.pdudjvme5zwofdxp@sasha-lappy> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180206014120.pdudjvme5zwofdxp@sasha-lappy> Sender: stable-owner@vger.kernel.org List-ID: On Tue, Feb 06, 2018 at 01:41:29AM +0000, Sasha Levin wrote: > On Mon, Feb 05, 2018 at 11:41:54AM +0000, Mark Brown wrote: > >On Sat, Feb 03, 2018 at 06:00:42PM +0000, Sasha Levin wrote: > >> From: Abhijeet Kumar > >> > >> [ Upstream commit d070f7c703ef26e3db613f24206823f916272fc6 ] > >> > >> In skylake platform, we hear a loud pop noise(0 dB) at start of > >> audio capture power up sequence. This patch removes the pop noise > >> from the recording by adding a delay before enabling ADC. > > > >> switch (event) { > >> case SND_SOC_DAPM_POST_PMU: > >> + msleep(125); > >> regmap_update_bits(nau8825->regmap, NAU8825_REG_ENA_CTRL, > > > >This is another one of these where I'm not convinced that backporting to > >stable isn't going to introduce regressions - it will fix problems on > >some systems but if someone really cares about a startup pop and has > >arranged to do something like discard the start of the audio where the > >pop occurs then this may cut off even more and cause them to miss > >things. > > It might cause regressions for users who worked around the issue, but it > may also fix the issue for users who didn't. I think that in general > we'd rather have mainline and stable trees have the same bugs and > breakage - we don't want surprises when users jump around between > kernels. Yes, being "bug compatible" is a key feature to have :) thanks, greg k-h