From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alper Nebi Yasak Subject: Re: Speaker pops with max98357a on rk3399-gru-kevin since v5.7 Date: Tue, 21 Jul 2020 01:40:14 +0300 Message-ID: <846feea6-e2b6-3a0e-b05f-d70e898f9ea5@gmail.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Tzung-Bi Shih Cc: Mark Brown , Liam Girdwood , Jaroslav Kysela , Takashi Iwai , Heiko Stuebner , ALSA development , Linux Kernel Mailing List , linux-rockchip@lists.infradead.org List-Id: linux-rockchip.vger.kernel.org On 17/07/2020 05:27, Tzung-Bi Shih wrote: > I am not convinced the pop comes from 128f825aeab7. Maybe some pre-existing defect in rk3399_gru_sound got exposed by 128f825aeab7 or the machine driver needs some changes to complement that commit? > (I don't have a rk3399-gru-kevin so I got another test machine with MAX98357A.) > (I was testing with and without an audio server.) Your observations are also a bit different from mine, which IMO also suggests the machine driver is the true culprit -- I'd guess the pops you hear would be from a different problem in your test machine's machine driver? (Let me restate my observations to contrast with yours, as I feel my previous explanation was too wordy:) > Observations: > - I can hear the pop either with or without 128f825aeab7 (with and > without sdmode-delay). I never hear pops without 128f825aeab7, but always hear pops with it. (no change when I remove "sdmode-delay" from the device-tree) > - The pop noise is not always. Higher probability after stopping > playback than before starting. I always hear one pop when starting playback, and two pops (with a few seconds between them) when stopping playback.