[PATCH] ALSA: usb-audio: work around streaming quirk for MacroSilicon MS2109

[Takashi Iwai]

On Mon, 10 Aug 2020 10:24:00 +0200,
Hector Martin wrote:
> 
> Further investigation of the L-R swap problem on the MS2109 reveals that
> the problem isn't that the channels are swapped, but rather that they
> are swapped and also out of phase by one sample. In other words, the
> issue is actually that the very first frame that comes from the hardware
> is a half-frame containing only the right channel, and after that
> everything becomes offset.
> 
> So introduce a new quirk field to drop the very first 2 bytes that come
> in after the format is configured and a capture stream starts. This puts
> the channels in phase and in the correct order.
> 
> Cc: stable at vger.kernel.org
> Signed-off-by: Hector Martin <marcan at marcan.st>

Hm, that's fairly weird behavior, but the workaround looks simple
enough, so now I applied as is.


thanks,

Takashi