[PATCH] ALSA: usb: Add Plantronics C320-M USB ctrl msg delay quirk

[Takashi Iwai]

On Wed, 03 Mar 2021 19:14:39 +0100,
John Ernberg wrote:
> 
> 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 at lysator.liu.se>
> Signed-off-by: John Ernberg <john.ernberg at 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!

Thanks, applied now.

It's a good timing, as I've recently got a bug report for the similar
device (C320) showing mysterious behavior on Teams :)


Takashi