On Sun, 18 Apr 2021 16:16:56 +0200, Geraldo Nascimento wrote: > > Em Dom, 18 de abr de 2021 09:45, Olivia Mackintosh <livvy@xxxxxxx> escreveu: > > > As a blind shot: might the stall be avoided by passing the recently > > introduced chip->playback_first flag? The revised patch is below. > > This appears to fix the issue, thank you! I am curious as to why this is > not required for Geraldo's DDJ-SR2. > > Heh, sometimes I think Takashi Iwai is psychic ;-) Heh, it was our luck that we've worked on the similar problem very recently. > Just kidding, he's "just" very talented and very experienced. Anyway, the > DDJ-SR2 is originally a Serato controller. It still requires two MIDI SysEx > messages to unmute the RCA inputs - engaging "Serato Mode" in marketing-speak. > > My point is that Pioneer may be a little more compliant / a little less > deviant from the UAC2 standard when designing gear for use with third-party > software. I think many devices require the implicit feedback seem following this pattern: for such devices, the full-duplex streams are mandatory, i.e. both streams have to be started always. And the implicit feedback is triggered at the later point for a proper sync. > My initial thought was that certain devices that restrict capture unless > regular SysEx/Control URBs are sent may mean that Playback first support > is required (e.g. 750, 850, 450). Please correct me if this intuition is > incorrect. As mentioned previously, it might be the difference of the PCM parameters to be deployed. I guess Geraldo didn't test speaker-test program but maybe only the standard sound backends like JACK, etc. In anyway, I'm going to format and submit the proper patch for merging. thanks, Takashi
