On Tue, 27 Oct 2020 08:18:41 +0100,
Keith Winstein wrote:
>
> On Mon, Oct 26, 2020 at 02:52:28PM +0100, Takashi Iwai wrote:
> > On Mon, 26 Oct 2020 09:01:43 +0100,
> > Keith Winstein wrote:
> > >
> > > Here is the patch again without line-wrapping.
> >
> > Could you put the patch description in the patch itself?
> > Basically I'm fine to merge this as is, just missing information for
> > git.
>
> Sure, here you go:
>
> >From 51fac91fa3a5da656ca6a49ca6cc98be7664efd7 Mon Sep 17 00:00:00 2001
> From: Keith Winstein <keithw@xxxxxxxxxxxxxxx>
> Date: Sun, 25 Oct 2020 22:05:47 -0700
> Subject: [PATCH] ALSA: usb-audio: Add implicit feedback quirk for Zoom UAC-2
>
> The Zoom UAC-2 USB audio interface provides an async playback endpoint ("1 OUT (ASYNC)") and
> capture endpoint ("2 IN (ASYNC)"), both with 2-channel S32_LE in 44.1, 48, 88.2, 96, 176.4,
> or 192 kilosamples/s. The device provides explicit feedback to adjust the host's playback
> rate, but the feedback appears unstable and biased relative to the device's capture rate.
> "alsaloop -t 1000" experiences playback underruns and tries to resample the captured audio
> to match the varying playback rate. Forcing the kernel to use implicit feedback appears to
> produce more stable results. This causes the host to transmit one playback sample for each
> capture sample received. (Zoom North America has been notified of this change.)
>
> Signed-off-by: Keith Winstein <keithw@xxxxxxxxxxxxxxx>
> Tested-by: Keith Winstein <keithw@xxxxxxxxxxxxxxx>
Applied now. Thanks.
Takashi
