Comment 75 for bug 1315212

# aplay -D plughw:CARD=CA0106 -v --buffer-size=128 /usr/share/sounds/alsa/Side_Left.wav
Playing WAVE '/usr/share/sounds/alsa/Side_Left.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Mono
Plug PCM: Route conversion PCM (sformat=S16_LE)
  Transformation table:
    0 <- 0
    1 <- 0
Its setup is:
  stream : PLAYBACK
  access : RW_INTERLEAVED
  format : S16_LE
  subformat : STD
  channels : 1
  rate : 48000
  exact rate : 48000 (48000/1)
  msbits : 16
  buffer_size : 128
  period_size : 32
  period_time : 666
  tstamp_mode : NONE
  period_step : 1
  avail_min : 32
  period_event : 0
  start_threshold : 128
  stop_threshold : 128
  silence_threshold: 0
  silence_size : 0
  boundary : 4611686018427387904
Slave: Hardware PCM card 0 'CA0106' device 0 subdevice 0
Its setup is:
  stream : PLAYBACK
  access : MMAP_INTERLEAVED
  format : S16_LE
  subformat : STD
  channels : 2
  rate : 48000
  exact rate : 48000 (48000/1)
  msbits : 16
  buffer_size : 128
  period_size : 32
  period_time : 666
  tstamp_mode : NONE
  period_step : 1
  avail_min : 32
  period_event : 0
  start_threshold : 128
  stop_threshold : 128
  silence_threshold: 0
  silence_size : 0
  boundary : 4611686018427387904
  appl_ptr : 0
  hw_ptr : 0

128 seems to be fine. It's not consistent, sometimes 64 works ok, sometimes it overruns (says so in the console and hitches). 128 has never overrun, neither visually (saying it in the console), nor audible (clicks/pops).