[PATCH] ALSA: firewire-motu: wait for notification when changing clock configuration for protocol v3

[Takashi Sakamoto]

This patch is for development period of v5.9 kernel.

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 at sakamocchi.jp>
---
 sound/firewire/motu/motu-protocol-v3.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/sound/firewire/motu/motu-protocol-v3.c b/sound/firewire/motu/motu-protocol-v3.c
index 01a47ac7bb2d..4e6b0e449ee4 100644
--- 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;
-- 
2.25.1