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From: Nandakumar Edamana <>
To: Geraldo Nascimento <>
Subject: Re: Behringer UMC202HD issues and a partial solution
Date: Fri, 14 Jan 2022 10:06:01 +0530	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <YeDw89KZOh4yG7c8@geday>

Hi Geraldo,
> Have you tried unloading the snd-usb-audio module and the reloading it
> with implicit_fb=1 as in "modprobe -r snd-usb-audio" and "modprobe
> snd-usb-audio implicit_fb=1" ?
> If not, try it. If it works and your playback issues are gone then
> your device may just need a quirk. If it doesn't work we still
> have dyndbg to go through.
It works! Had to switch the devices and options back and forth in 
(sometimes needed even for the choppy playback), but it works.

So why did my quirks didn't work? Maybe I gave the wrong numbers? Or the 
was unreachable (I didn't put printk()s, sorry). I guessed the combos from
`lsusb -v` output, and even tried the combos that didn't make any sense
(because I didn't know what I was doing).

Here's what I tried, one after another (added to 
playback_implicit_fb_quirks in

IMPLICIT_FB_GENERIC_DEV(0x1397, 0x0507),

/* Didn't work */
IMPLICIT_FB_FIXED_DEV(0x1397, 0x0507, 0x84, 1),

/* Interface 2 is actually Capture as per `cat /proc/asound/card1/stream0`,
  * but "Implicit feedback Data" is found under that
  * (Interface 1 has explicit Feedback), and a Scarlett quirk seemed to use
  * a capture interface in playback_implicit_fb_quirks
  * (I know that it's a capture interface from `lsusb` output posted by 
  * online)
/* Didn't work */
IMPLICIT_FB_FIXED_DEV(0x1397, 0x0507, 0x88, 2),

/* Didn't work */
/* What am I doing with 0x08 ? */
IMPLICIT_FB_FIXED_DEV(0x1397, 0x0507, 0x08, 1),

/* Didn't work */
/* Why BOTH? But what's FIXED at first? Didn't find any doc. */
IMPLICIT_FB_BOTH_DEV(0x1397, 0x0507, 0x84, 1),

/* Didn't work */
IMPLICIT_FB_SKIP_DEV(0x1397, 0x0507),
> Last but not least, please use a vanilla kernel for these tests.
I built it using the source from, not apt. But I've used 
and I think patches are being applied while installing the kernel 
(currently I'm
using my daily driver installation for this). If it has to be more pure, 
I 'll
try. BTW, do you have any distro to recommend that has a near-vanilla 
kernel for
experiments like this?

Another question: assuming a quirk gets added for this device, is there any
chance that the quirk would break the experience for those who are already
using the device (possibly a different revision, but the same ID [1]) 
any issues?


Thank you,

Nandakumar Edamana

GPG Key:
GPG Key Fingerprint: BA6B 8FDE 644F F861 B638  3E2F 45D6 05FC 646A F75D

  reply	other threads:[~2022-01-14  4:37 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-13 14:37 Behringer UMC202HD issues and a partial solution Nandakumar Edamana
2022-01-13 19:00 ` Geraldo Nascimento
2022-01-14  2:34   ` Nandakumar Edamana
2022-01-14  3:41     ` Geraldo Nascimento
2022-01-14  4:36       ` Nandakumar Edamana [this message]
2022-01-14  7:44         ` Geraldo Nascimento
2022-01-14 13:39           ` Nandakumar Edamana
2022-01-14 22:28             ` Geraldo Nascimento
     [not found]               ` <>
2022-01-16  1:00                 ` Geraldo Nascimento
2022-01-18 11:20                   ` Nandakumar Edamana
2022-01-18 19:20                     ` Geraldo Nascimento

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