[PATCH] ALSA: usb-audio: Apply async workaround for Scarlett 2i4 2nd gen

[Alexander Tsoy]

В Вт, 21/04/2020 в 21:31 +0200, Takashi Iwai пишет:
> On Tue, 21 Apr 2020 21:09:08 +0200,
> Alexander Tsoy wrote:
> > Due to rounding error driver sometimes incorrectly calculate next
> > packet
> > size, which results in audible clicks on devices with synchronous
> > playback
> > endpoints. For example on a high speed bus and a sample rate 44.1
> > kHz it
> > loses one sample every ~40.9 seconds. Fortunately playback
> > interface on
> > Scarlett 2i4 2nd gen has a working explicit feedback endpoint, so
> > we can
> > switch playback data endpoint to asynchronous mode as a workaround.
> > 
> > Signed-off-by: Alexander Tsoy <alexander at tsoy.me>
> 
> Applied now, thanks.
> 
> I wonder, though, whether we can correct the rounding error in the
> driver code, too.

I'm not sure if it's possible with currently used Q16.16 arithmetic.