ALSA: dice: get the number of MBLA data channel at opening PCM substream

This commit is a preparation to remove members related to channel cache
for the number of channels for multi bit linear audio data and MIDI
ports. This commit changes the way to get the number of multi bit linear
audio data channel. It's directly retrieved by asynchronous transactions
to some registers.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/firewire/dice/dice-pcm.c b/sound/firewire/dice/dice-pcm.c
index 0b6e6bbed4b8fdf16f83c783619a25957b870a96..a5c9b58655ef2f69141a66e440480ac4f6049bc6 100644 (file)
--- a/sound/firewire/dice/dice-pcm.c
+++ b/sound/firewire/dice/dice-pcm.c
@@ -294,17 +294,30 @@ int snd_dice_create_pcm(struct snd_dice *dice)
                .page      = snd_pcm_lib_get_vmalloc_page,
                .mmap      = snd_pcm_lib_mmap_vmalloc,
        };
+       __be32 reg;
        struct snd_pcm *pcm;
-       unsigned int i, capture, playback;
+       unsigned int capture, playback;
        int err;
 
-       capture = playback = 0;
-       for (i = 0; i < 3; i++) {
-               if (dice->tx_channels[i] > 0)
-                       capture = 1;
-               if (dice->rx_channels[i] > 0)
-                       playback = 1;
-       }
+       /*
+        * Check whether PCM substreams are required.
+        *
+        * TODO: in the case that any PCM substreams are not avail at a certain
+        * sampling transfer frequency?
+        */
+       err = snd_dice_transaction_read_tx(dice, TX_NUMBER_AUDIO,
+                                          &reg, sizeof(reg));
+       if (err < 0)
+               return err;
+       if (be32_to_cpu(reg) > 0)
+               capture = 1;
+
+       err = snd_dice_transaction_read_rx(dice, RX_NUMBER_AUDIO,
+                                          &reg, sizeof(reg));
+       if (err < 0)
+               return err;
+       if (be32_to_cpu(reg) > 0)
+               playback = 1;
 
        err = snd_pcm_new(dice->card, "DICE", 0, playback, capture, &pcm);
        if (err < 0)