ALSA: firewire-motu: wait for notification when changing clock configuration for...

It costs expensive to change clock configuration for models of protocol
version 3. In current implementation, speculative strategy is used to
finish the operation; just waiting for 4 seconds. As long as I investigate,
when accepting and changing clock status actually, the device sends
notification with mask.

This commit uses wise way to wait for the notification after changing
sampling clock rate during 4 seconds.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20200614141221.53527-1-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/firewire/motu/motu-protocol-v3.c b/sound/firewire/motu/motu-protocol-v3.c
index 01a47ac..4e6b0e4 100644 (file)
--- a/sound/firewire/motu/motu-protocol-v3.c
+++ b/sound/firewire/motu/motu-protocol-v3.c
@@ -24,6 +24,9 @@
 #define  V3_NO_ADAT_OPT_OUT_IFACE_A    0x00040000
 #define  V3_NO_ADAT_OPT_OUT_IFACE_B    0x00400000
 
+#define V3_MSG_FLAG_CLK_CHANGED                0x00000002
+#define V3_CLK_WAIT_MSEC               4000
+
 int snd_motu_protocol_v3_get_clock_rate(struct snd_motu *motu,
                                        unsigned int *rate)
 {
@@ -79,9 +82,16 @@ int snd_motu_protocol_v3_set_clock_rate(struct snd_motu *motu,
                return err;
 
        if (need_to_wait) {
-               /* Cost expensive. */
-               if (msleep_interruptible(4000) > 0)
-                       return -EINTR;
+               int result;
+
+               motu->msg = 0;
+               result = wait_event_interruptible_timeout(motu->hwdep_wait,
+                                       motu->msg & V3_MSG_FLAG_CLK_CHANGED,
+                                       msecs_to_jiffies(V3_CLK_WAIT_MSEC));
+               if (result < 0)
+                       return result;
+               if (result == 0)
+                       return -ETIMEDOUT;
        }
 
        return 0;