+<code>hw_ptr_alignment</code> specifies slave application and hw
+pointer alignment type. By default hw_ptr_alignment is auto. Below are
+the possible configurations:
+- no: minimal latency with minimal frames dropped at startup. But
+ wakeup of application (return from snd_pcm_wait() or poll()) can
+ take up to 2 * period.
+- roundup: It is guaranteed that all frames will be played at
+ startup. But the latency will increase upto period-1 frames.
+- rounddown: It is guaranteed that a wakeup will happen for each
+ period and frames can be written from application. But on startup
+ upto period-1 frames will be dropped.
+- auto: Selects the best approach depending on the used period and
+ buffer size.
+ If the application buffer size is < 2 * application period,
+ "roundup" will be selected to avoid over runs. If the slave_period
+ is < 10ms we could expect that there are low latency
+ requirements. Therefore "rounddown" will be chosen to avoid long
+ wakeup times. Else "no" will be chosen.
+