[alsa-devel] BOSS GT-1 USB audio and implicit feedback

[Jens Verwiebe]

Hi man

I feel i#am in the same boat as you with the helix.

Just its other way round: it works generally wih rare sync glizches 
depending on buffer.

Or if i force an implicit feedback endpoint it fails, but the created 
endpoints re correct.

Example:

[ 6449.240683] usb 9-1.3: setting usb interface 3:1
[ 6449.240685] usb 9-1.3: Creating new capture data endpoint #83
[ 6449.240811] usb 9-1.3: Setting params for ep #83 (type 0, 12 urbs), ret=0
[ 6449.241262] usb 9-1.3: setting usb interface 2:1
[ 6449.241263] usb 9-1.3: Creating new playback data endpoint #3
[ 6449.241480] usb 9-1.3: Setting params for ep #3 (type 0, 3 urbs), ret=0
[ 6449.241481] usb 9-1.3: Starting data EP @000000003cb8615a
[ 6449.241980] usb 9-1.3: Starting data EP @000000001cd170f7

works, but glitches every 20 minutes with a 256 buffer and 3 periods aka 
there is NO sync active.

.. while

[ 6063.161280] usb 9-1.3: Setting params for ep #83 (type 0, 12 urbs), ret=0
[ 6063.161734] usb 9-1.3: setting usb interface 2:1
[ 6063.161735] usb 9-1.3: Creating new playback data endpoint #3
[ 6063.161737] usb 9-1.3: Re-using EP 83 in iface 3,1 @000000008c3855fb
[ 6063.162033] usb 9-1.3: Setting params for ep #3 (type 0, 12 urbs), ret=0
[ 6063.162035] usb 9-1.3: match_endpoint_audioformats: (fmt 
@000000006290dadc) score 2
[ 6063.162040] usb 9-1.3: Setting params for ep #83 (type 0, 12 urbs), ret=0
[ 6063.162040] usb 9-1.3: Starting data EP @000000001d36b573
[ 6063.162466] usb 9-1.3: Starting sync EP @000000008c3855fb
[ 6063.162977] usb 9-1.3: Starting data EP @000000008c3855fb

is with a forced sync endpoint, but it will not finally setup.

Its the same as with your device that implicit feedback with "shared" 
endpoints for in data seems to be a problem.

Unfortunately i alsked around here since 2 years but never got a result.

Sidenote: i have the chance to compare to the nac side if this helps ( 
helix works driverless with initial 48kHz there too )

Perhaps more heads some day gets their brains wrapped around this.


Cheers ... Jens

-- 

Jens Verwiebe
Allerskehre 44 - 22309 Hamburg

Tel.: +49 40 68 78 50
mailto: info at jensverwiebe.de
web: https://www.jensverwiebe.de