ALSA: usb-audio: Eliminate noise at the start of DSD playback.

[epicfrequency]

Copy mainline DSD playback pop noise fix

https://github.com/torvalds/linux/commit/012007309133d21a5a7eae3f552c03ac061a2b51#diff-cc9fc192670bbec31122ad6874641755

[Problem] In some USB DACs, a terrible pop noise comes to be heard at the start of DSD playback (in the following situations).

• play first DSD track
• change from PCM track to DSD track
• change from DSD64 track to DSD128 track (and etc...)
• seek DSD track
• Fast-Forward/Rewind DSD track

[Cause] At the start of playback, there is a little silence. The silence bit pattern "0x69" is required on DSD mode, but it is not like that.

[Solution] This patch adds DSD silence pattern to the endpoint settings.

Signed-off-by: Nobutaka Okabe nob77413@gmail.com Signed-off-by: Takashi Iwai tiwai@suse.de

[mdrjr]

Thank you for backporting that :)