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));