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.
