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

Thu Apr 8 07:05:01 CEST 2021

>
> Mike, I just realize I missed reply-to-all once again.

In case you were wondering, I was looking for a sync_ep event right in the
start of the loading of snd-usb-audio. It happens inside pcm.c. If you see
one of those specifically let me know.

With my Pioneer device, the DDJ-SR2, snd-usb-audio recognized the device's
implicit feedback EP as sync_ep and that prevented JACK from starting.

Em Qua, 7 de abr de 2021 23:47, Mike Oliphant <oliphant at nostatic.org>
> escreveu:
>
>> Hi Geraldo - I had the same thought and I have tried enabling playback
>> feedback while turning off capture feedback without my endpoint patch. It
>> doesn't work - at least not on the GT-1. Playback/capture fails to start.
>>
>
> Would you mind sharing the dyndbg logs for the failure case from the point
> you connect the device, and trying to start JACK?
>
> Sometimes failures elucidate more than success cases.
>
>
>> Speaking of testing, if you (or anyone else following this discussion)
>> have one of these Roland/BOSS devices, it would be great if you could try
>> testing with playback feedback enabled and my endpoint.c workaround.
>>
>
> I don't have the hardware, but I'm sure it works. The problem is that
> endpoint.c code really shouldn't be disabled unless all the other options
> fail, and even then, I'm not so sure the maintainers will be so willing to
> disable it. So let's keep some other options on the table by debugging a
> little further.
>
> Thank you,
> Geraldo
>
>
>> Mike
>>
>> On Wed, Apr 7, 2021 at 7:21 PM Geraldo Nascimento <
>> geraldogabriel at gmail.com> wrote:
>>
>>> Thanks, Mike, one thing I can tell you right off the bat is that if you
>>> turn implicit feedback sync on for both endpoints at the same time like you
>>> mentioned, without your workaround inside endpoint.c, they most likely will
>>> stall because they would both be waiting for each other to start.
>>>
>>> Have you tried engaging the generic implicit feedback sync just for the
>>> playback, thereby commenting out the capture implicit feedback entries, and
>>> re-enabling snd_usb_endpoint_implicit_feedback_sink(ep) inside endpoint.c?
>>> Does playback still fail to start?
>>>
>>> If you choose to perform this simple test please share with us the
>>> test's dyndbg logs right from the moment you turn on the device, not just
>>> after you start jackd.
>>>
>>> Sorry for the endless do-this, do-that. Such is the pace of teledebugging
>>>
>>>
>>> Em Qua, 7 de abr de 2021 21:38, Mike Oliphant <oliphant at nostatic.org>
>>> escreveu:
>>>
>>>> Geraldo - here is the dmesg output when starting up jackd for
>>>> capture/playback:
>>>>
>>>> With my patch:
>>>>
>>>> [  136.734081] usb 3-1.2: Open EP 0x8e, iface=2:1, idx=0
>>>> [  136.734088] usb 3-1.2:   channels=2, rate=44100, format=S32_LE,
>>>> period_bytes=256, periods=2, implicit_fb=0
>>>> [  136.734092] usb 3-1.2: Setting usb interface 2:0 for EP 0x8e
>>>> [  136.734233] usb 3-1.2: Setting usb interface 2:1 for EP 0x8e
>>>> [  136.734381] usb 3-1.2: 2:1 Set sample rate 44100, clock 0
>>>> [  136.734388] usb 3-1.2: Setting params for data EP 0x8e, pipe 0x70480
>>>> [  136.734394] usb 3-1.2: Set up 12 URBS, ret=0
>>>> [  136.734466] usb 3-1.2: Open EP 0xd, iface=1:1, idx=0
>>>> [  136.734468] usb 3-1.2:   channels=2, rate=44100, format=S32_LE,
>>>> period_bytes=256, periods=2, implicit_fb=1
>>>> [  136.734471] usb 3-1.2: Reopened EP 0x8e (count 1)
>>>> [  136.734473] usb 3-1.2: Setting usb interface 1:0 for EP 0xd
>>>> [  136.734605] usb 3-1.2: Setting usb interface 1:1 for EP 0xd
>>>> [  136.734762] usb 3-1.2: 1:1 Set sample rate 44100, clock 0
>>>> [  136.734774] usb 3-1.2: Setting params for data EP 0xd, pipe 0x68400
>>>> [  136.734781] usb 3-1.2: Set up 12 URBS, ret=0
>>>> [  136.734830] usb 3-1.2: Starting data EP 0xd (running 0)
>>>> [  136.734873] usb 3-1.2: 12 URBs submitted for EP 0xd
>>>> [  136.734876] usb 3-1.2: Starting data EP 0x8e (running 0)
>>>> [  136.734906] usb 3-1.2: 12 URBs submitted for EP 0x8e
>>>> [  136.740627] usb 3-1.2: Starting data EP 0x8e (running 1)
>>>> [  136.740634] usb 3-1.2: 2:1 Start Capture PCM
>>>> [  136.740635] usb 3-1.2: 1:1 Start Playback PCM
>>>>
>>>>
>>>> With the unpatched kernel:
>>>>
>>>> [  344.813203] usb 3-1.2: Open EP 0x8e, iface=2:1, idx=0
>>>> [  344.813210] usb 3-1.2:   channels=2, rate=44100, format=S32_LE,
>>>> period_bytes=256, periods=2, implicit_fb=1
>>>> [  344.813213] usb 3-1.2: Open EP 0xd, iface=1:1, idx=0
>>>> [  344.813215] usb 3-1.2:   channels=2, rate=44100, format=S32_LE,
>>>> period_bytes=256, periods=2, implicit_fb=0
>>>> [  344.813217] usb 3-1.2: Setting usb interface 2:0 for EP 0x8e
>>>> [  344.813367] usb 3-1.2: Setting usb interface 2:1 for EP 0x8e
>>>> [  344.813494] usb 3-1.2: 2:1 Set sample rate 44100, clock 0
>>>> [  344.813503] usb 3-1.2: Setting params for data EP 0x8e, pipe 0x70580
>>>> [  344.813509] usb 3-1.2: Set up 12 URBS, ret=0
>>>> [  344.813513] usb 3-1.2: Setting usb interface 1:0 for EP 0xd
>>>> [  344.813587] usb 3-1.2: Setting usb interface 1:1 for EP 0xd
>>>> [  344.813758] usb 3-1.2: 1:1 Set sample rate 44100, clock 0
>>>> [  344.813765] usb 3-1.2: Setting params for data EP 0xd, pipe 0x68500
>>>> [  344.813770] usb 3-1.2: Set up 2 URBS, ret=0
>>>> [  344.813858] usb 3-1.2: Reopened EP 0xd (count 1)
>>>> [  344.813883] usb 3-1.2: Starting data EP 0xd (running 0)
>>>> [  344.813899] usb 3-1.2: 2 URBs submitted for EP 0xd
>>>> [  344.819499] usb 3-1.2: Starting data EP 0x8e (running 0)
>>>> [  344.819532] usb 3-1.2: 12 URBs submitted for EP 0x8e
>>>> [  344.819535] usb 3-1.2: Starting data EP 0xd (running 1)
>>>> [  344.819538] usb 3-1.2: 2:1 Start Capture PCM
>>>> [  344.819540] usb 3-1.2: 1:1 Start Playback PCM
>>>> [  344.820663] usb 3-1.2: Stopping data EP 0xd (running 2)
>>>> [  344.820688] usb 3-1.2: Stopping data EP 0x8e (running 1)
>>>> [  344.820693] usb 3-1.2: 2:1 Stop Capture PCM
>>>> [  344.820695] usb 3-1.2: Stopping data EP 0xd (running 1)
>>>> [  344.820697] usb 3-1.2: 1:1 Stop Playback PCM
>>>> [  344.833799] usb 3-1.2: Starting data EP 0xd (running 0)
>>>> [  344.833852] usb 3-1.2: 2 URBs submitted for EP 0xd
>>>> [  344.833867] usb 3-1.2: Starting data EP 0x8e (running 0)
>>>> [  344.833888] usb 3-1.2: 12 URBs submitted for EP 0x8e
>>>> [  344.833890] usb 3-1.2: Starting data EP 0xd (running 1)
>>>> [  344.833891] usb 3-1.2: 2:1 Start Capture PCM
>>>> [  344.833893] usb 3-1.2: 1:1 Start Playback PCM
>>>>
>>>> On Wed, Apr 7, 2021 at 1:30 PM Geraldo Nascimento <
>>>> geraldogabriel at gmail.com> wrote:
>>>>
>>>>> 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.
>>>>>>>>
>>>>>>>