linux-stable/sound
Keith Winstein f15cfca818 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>
Cc: <stable@vger.kernel.org>
BugLink: https://lore.kernel.org/r/20201027071841.GA164525@trolley.csail.mit.edu
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2020-10-27 08:25:04 +01:00
..
ac97 ALSA: ac97: (cosmetic) align argument names 2020-09-03 09:27:27 +02:00
aoa ALSA: aoa: i2sbus: use DECLARE_COMPLETION_ONSTACK() macro 2020-09-03 09:26:52 +02:00
arm
atmel ALSA: atmel: ac97: clarify operator precedence 2020-09-03 09:27:34 +02:00
core ALSA: fix kernel-doc markups 2020-10-26 15:26:31 +01:00
drivers ALSA: portman2x4: fix repeated word 'if' 2020-10-06 18:08:19 +02:00
firewire ALSA: fireworks: use semicolons rather than commas to separate statements 2020-10-12 08:51:51 +02:00
hda ASoC: Updates for v5.10 2020-10-12 16:08:57 +02:00
i2c
isa sound fixes for 5.9-rc2 2020-08-21 10:07:54 -07:00
mips hal2: convert to dma_alloc_noncoherent 2020-09-25 06:20:44 +02:00
oss ALSA: Use fallthrough pseudo-keyword 2020-07-09 13:01:29 +02:00
parisc
pci ALSA: hda - Fix the return value if cb func is already registered 2020-10-22 08:17:02 +02:00
pcmcia ALSA: Use fallthrough pseudo-keyword 2020-07-09 13:01:29 +02:00
ppc treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
sh
soc ALSA: fix kernel-doc markups 2020-10-26 15:26:31 +01:00
sparc ALSA: sparc: dbri: fix repeated word 'the' 2020-10-17 09:58:35 +02:00
spi
synth
usb ALSA: usb-audio: Add implicit feedback quirk for Zoom UAC-2 2020-10-27 08:25:04 +01:00
x86 ALSA: hda: use consistent HDAudio spelling in comments/docs 2020-09-02 19:31:32 +02:00
xen ALSA: xen: Remove superfluous fall through comments 2020-07-09 19:10:37 +02:00
ac97_bus.c
Kconfig
last.c
Makefile
sound_core.c