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 5.11-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-5.11 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 @@ -1670,6 +1670,14 @@ 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-5.11/alsa-usb-add-plantronics-c320-m-usb-ctrl-msg-delay-quirk.patch