This is a note to let you know that I've just added the patch titled
ALSA: usb: Add Plantronics C320-M USB ctrl msg delay quirk
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
alsa-usb-add-plantronics-c320-m-usb-ctrl-msg-delay-quirk.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From fc7c5c208eb7bc2df3a9f4234f14eca250001cb6 Mon Sep 17 00:00:00 2001
From: John Ernberg <john.ernberg@xxxxxxxx>
Date: Wed, 3 Mar 2021 18:14:39 +0000
Subject: ALSA: usb: Add Plantronics C320-M USB ctrl msg delay quirk
From: John Ernberg <john.ernberg@xxxxxxxx>
commit fc7c5c208eb7bc2df3a9f4234f14eca250001cb6 upstream.
The microphone in the Plantronics C320-M headset will randomly
fail to initialize properly, at least when using Microsoft Teams.
Introducing a 20ms delay on the control messages appears to
resolve the issue.
Link: https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/issues/1065
Tested-by: Andreas Kempe <kempe@xxxxxxxxxxxxxx>
Signed-off-by: John Ernberg <john.ernberg@xxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210303181405.39835-1-john.ernberg@xxxxxxxx
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
sound/usb/quirks.c | 8 ++++++++
1 file changed, 8 insertions(+)
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -1338,6 +1338,14 @@ void snd_usb_ctl_msg_quirk(struct usb_de
&& (requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
msleep(20);
+ /*
+ * Plantronics C320-M needs a delay to avoid random
+ * microhpone failures.
+ */
+ if (chip->usb_id == USB_ID(0x047f, 0xc025) &&
+ (requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
+ msleep(20);
+
/* Zoom R16/24, many Logitech(at least H650e/H570e/BCC950),
* Jabra 550a, Kingston HyperX needs a tiny delay here,
* otherwise requests like get/set frequency return
Patches currently in stable-queue which might be from john.ernberg@xxxxxxxx are
queue-4.19/alsa-usb-add-plantronics-c320-m-usb-ctrl-msg-delay-quirk.patch
