diff options
Diffstat (limited to 'sound/firewire/dice.c')
| -rw-r--r-- | sound/firewire/dice.c | 29 |
1 files changed, 20 insertions, 9 deletions
diff --git a/sound/firewire/dice.c b/sound/firewire/dice.c index a9a30c0161f..e3a04d69c85 100644 --- a/sound/firewire/dice.c +++ b/sound/firewire/dice.c @@ -567,10 +567,14 @@ static int dice_hw_params(struct snd_pcm_substream *substream, return err; /* - * At rates above 96 kHz, pretend that the stream runs at half the - * actual sample rate with twice the number of channels; two samples - * of a channel are stored consecutively in the packet. Requires - * blocking mode and PCM buffer size should be aligned to SYT_INTERVAL. + * At 176.4/192.0 kHz, Dice has a quirk to transfer two PCM frames in + * one data block of AMDTP packet. Thus sampling transfer frequency is + * a half of PCM sampling frequency, i.e. PCM frames at 192.0 kHz are + * transferred on AMDTP packets at 96 kHz. Two successive samples of a + * channel are stored consecutively in the packet. This quirk is called + * as 'Dual Wire'. + * For this quirk, blocking mode is required and PCM buffer size should + * be aligned to SYT_INTERVAL. */ channels = params_channels(hw_params); if (rate_index > 4) { @@ -579,18 +583,25 @@ static int dice_hw_params(struct snd_pcm_substream *substream, return err; } - for (i = 0; i < channels; i++) { - dice->stream.pcm_positions[i * 2] = i; - dice->stream.pcm_positions[i * 2 + 1] = i + channels; - } - rate /= 2; channels *= 2; + dice->stream.double_pcm_frames = true; + } else { + dice->stream.double_pcm_frames = false; } mode = rate_index_to_mode(rate_index); amdtp_stream_set_parameters(&dice->stream, rate, channels, dice->rx_midi_ports[mode]); + if (rate_index > 4) { + channels /= 2; + + for (i = 0; i < channels; i++) { + dice->stream.pcm_positions[i] = i * 2; + dice->stream.pcm_positions[i + channels] = i * 2 + 1; + } + } + amdtp_stream_set_pcm_format(&dice->stream, params_format(hw_params)); |