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-rw-r--r--sound/firewire/dice.c29
1 files changed, 20 insertions, 9 deletions
diff --git a/sound/firewire/dice.c b/sound/firewire/dice.c
index a9a30c0161f1..e3a04d69c853 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));