Implicit feedback on BOSS GT-1, the saga continues...

[Geraldo Nascimento]

Em Qua, 7 de abr de 2021 17:16, Mike Oliphant <oliphant at nostatic.org>
escreveu:

> Hi Geraldo - I don't have that patch applied, but it shouldn't make any
> behavioral difference - it just seems to be simplifying the code.
>

Point taken.


> The issue is that the BOSS GT-1 *does* need implicit feedback on playback
> to avoid clock timing issues, and the current behavior is disabling that
> feedback.
>

Mike, would you mind posting some dyndbg logs for both the stock behaviour
and your endpoint.c/generic quirk modified behaviour?

Just add snd_usb_audio.dyndbg=+p to your kernel options and please share
the logs.


> Mike
>
> On Wed, Apr 7, 2021 at 1:04 PM Geraldo Nascimento <
> geraldogabriel at gmail.com> wrote:
>
>> Hey Mike, did you catch the latest patch by Takashi Iwai for capture
>> quirky devices?
>>
>> You can find it here:
>> https://patchwork.kernel.org/project/alsa-devel/patch/20210406113837.32041-1-tiwai@suse.de/
>>
>> Em Qua, 7 de abr de 2021 16:55, Mike Oliphant <oliphant at nostatic.org>
>> escreveu:
>>
>>> I had thought that the recent implicit feedback changes were fully
>>> working
>>> on the BOSS GT-1, but it turns out that I just hadn't tested well enough.
>>>
>>> Audio playback and capture works, but with periodic dropouts. I get the
>>> exact same behavior as I did with the quirk to completely disable
>>> implicit
>>> feedback. Without the implicit feedback, you get dropouts from clock
>>> drift
>>> - how bad probably varies from card to card. On mine it is every second
>>> or
>>> so.
>>>
>>> If I switch playback feedback for the GT-1 to generic by doing
>>> "IMPLICIT_FB_GENERIC_DEV(0x0582, 0x01d6)", I get the previous old
>>> behavior,
>>> which is that playback completely fails to start.
>>>
>>> With generic playback feedback, and using my previous patch to endpoint.c
>>> to avoid playback waiting on capture mentioned here:
>>>
>>>
>>> https://mailman.alsa-project.org/pipermail/alsa-devel/2020-January/161951.html
>>>
>>> playback and capture work perfectly for me.
>>>
>>