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@lysator.liu.se Signed-off-by: John Ernberg john.ernberg@actia.se ---

Note: Microsoft Teams is the only application tests have been performed with and no other kinds of investigations have been performed, like USB packet logging. Originally reported as a possible PulseAudio issue, where it was suggested to try a delay quirk in the kernel. If other tests should be performed, please let me know which tests and I will try to do them.

All testing was done on 5.10, patch was then applied on sound.git master for submission

I did not register to the mailing lists, please keep me CC on any comments. Thanks!

sound/usb/quirks.c | 8 ++++++++ 1 file changed, 8 insertions(+)

diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c index d02dac5fcd40..a31b7db92b1e 100644 --- a/sound/usb/quirks.c +++ b/sound/usb/quirks.c @@ -1673,6 +1673,14 @@ void snd_usb_ctl_msg_quirk(struct usb_device *dev, unsigned int pipe, && (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