From: Takashi Iwai <tiwai@suse.de>
To: Keith Winstein <keithw@cs.stanford.edu>
Cc: alsa-devel@alsa-project.org
Subject: Re: [PATCH] ALSA: usb-audio: Add implicit feedback quirk for Zoom UAC-2
Date: Tue, 27 Oct 2020 08:27:31 +0100 [thread overview]
Message-ID: <s5ho8ko2knw.wl-tiwai@suse.de> (raw)
In-Reply-To: <20201027071841.GA164525@trolley.csail.mit.edu>
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@cs.stanford.edu>
> 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@cs.stanford.edu>
> Tested-by: Keith Winstein <keithw@cs.stanford.edu>
Applied now. Thanks.
Takashi
prev parent reply other threads:[~2020-10-27 7:28 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-26 7:26 [PATCH] ALSA: usb-audio: Add implicit feedback quirk for Zoom UAC-2 Keith Winstein
2020-10-26 8:01 ` Keith Winstein
2020-10-26 13:52 ` Takashi Iwai
2020-10-27 7:18 ` Keith Winstein
2020-10-27 7:27 ` Takashi Iwai [this message]
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