[alsa-devel] [PATCH] ALSA: usb-audio: Disable quirks for BOSS Katana amplifiers

[Mike Oliphant]

Keith - are you getting an implicit feedback endpoint created when you run
with the patch?

When I patched the GT-1 device ID into the quirk code, I ended up with no
implicit feedback endpoint created. Without running in implicit feedback
mode, I assume that you are relying on how well the clocks match. In my
case, my card's clock was a bit fast. If I hardcoded the sample rate in
'sound/usb/format.c' to 44105, my pops and crackles mostly went away - more
like every few minutes instead of every few seconds.

Maybe your card just has a clock closer to 44100? Or, as I said in my last
message, maybe something else has changed in the kernel since earlier this
year?

Mike

On Wed, Oct 14, 2020 at 8:35 AM Mailing Lists <maillist at superlative.org>
wrote:

> Hi Mike,
> That's odd. I've been using the patches in this thread with both my GT-001
> and my GT-1 with no issues for a few weeks now. Of course that might be
> pure dumb luck and differences in hardware, interrupts, and so on.
>
> Cheers,
>
> Keith
>
> On Wed, 14 Oct 2020 at 16:19, Mike Oliphant <oliphant at nostatic.org> wrote:
>
>> When I tried this change earlier this year on the BOSS GT-1, it enabled
>> sound output on the card (which was not previously working), but with
>> significant issues. It resulted in frequent pops and crackles - presumably
>> because of the loss of synchronization using implicit feedback.
>>
>> This was the fix that ended up working for me:
>>
>>
>> https://mailman.alsa-project.org/pipermail/alsa-devel/2020-January/161951.html
>>
>> But maybe something else has changed in the handling of implicit feedback
>> since then?
>>
>> Mike
>>
>> On Wed, Oct 14, 2020 at 5:17 AM Mailing Lists <maillist at superlative.org>
>> wrote:
>>
>>> Following up on this, it appears there are a bunch of the
>>> newer-generation Roland/Boss devices which need similar treatment.
>>>
>>> So far I have tested the GT-1, the GT-001, and the BR-80, and others
>>> have reported the RC-300 as working with similar modifications. I have been
>>> using the following change to the code in pcm.c
>>> set_sync_ep_implicit_fb_quirk:
>>>
>>>     case USB_ID(0x0582, 0x01d8): /* BOSS Katana */
>>>     case USB_ID(0x0582, 0x0130): /* BOSS Micro BR-80 */
>>>     case USB_ID(0x0582, 0x0138): /* BOSS RC-300 */
>>>     case USB_ID(0x0582, 0x01d6): /* BOSS GT-1 */
>>>     case USB_ID(0x0582, 0x01e5): /* BOSS GT-001 */
>>> /* BOSS Katana amplifiers and many other newer BOSS devices do not need
>>> quirks */
>>>
>>> There's probably others too, such as the GT-100 (I believe the GT-001
>>> and GT-100 have similar hardware).
>>>
>>> My question is, should this just be submitted as a patch to pcm.c or
>>> would it be better handled in quirks and, if so, how?
>>>
>>> Or something else?
>>>
>>> Personally, I dislike the approach of hard-coding exceptions into core
>>> code as it seems that's what quirks are there for, but there seems to be a
>>> whole bunch of exceptions in there already.
>>>
>>> Cheers,
>>>
>>> Keith
>>>
>>> On Thu, 17 Oct 2019 at 09:20, Takashi Iwai <tiwai at suse.de> wrote:
>>>
>>>> On Fri, 11 Oct 2019 19:19:36 +0200,
>>>> Szabolcs Szőke wrote:
>>>> >
>>>> > BOSS Katana amplifiers cannot be used for recording or playback if
>>>> quirks
>>>> > are applied
>>>> >
>>>> > BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=195223
>>>> > Signed-off-by: Szabolcs Szőke <szszoke.code at gmail.com>
>>>>
>>>> Applied now.  Thanks.
>>>>
>>>>
>>>> Takashi
>>>>
>>>> >
>>>> > ---
>>>> >  sound/usb/pcm.c | 3 +++
>>>> >  1 file changed, 3 insertions(+)
>>>> >
>>>> > diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
>>>> > index 33cd26763c0e..daadb0c66eee 100644
>>>> > --- a/sound/usb/pcm.c
>>>> > +++ b/sound/usb/pcm.c
>>>> > @@ -348,6 +348,9 @@ static int set_sync_ep_implicit_fb_quirk(struct
>>>> snd_usb_substream *subs,
>>>> >               ep = 0x84;
>>>> >               ifnum = 0;
>>>> >               goto add_sync_ep_from_ifnum;
>>>> > +     case USB_ID(0x0582, 0x01d8): /* BOSS Katana */
>>>> > +             /* BOSS Katana amplifiers do not need quirks */
>>>> > +             return 0;
>>>> >       }
>>>> >
>>>> >       if (attr == USB_ENDPOINT_SYNC_ASYNC &&
>>>> > --
>>>> > 2.20.1
>>>> >
>>>> _______________________________________________
>>>> Alsa-devel mailing list
>>>> Alsa-devel at alsa-project.org
>>>> https://mailman.alsa-project.org/mailman/listinfo/alsa-devel
>>>>
>>>
>>>
>>> --
>>> --
>>> Keith A Milner
>>>
>>
>
> --
> --
> Keith A Milner
>