Commit 67539867 authored Jun 14, 2020 by Takashi Sakamoto Committed by Takashi Iwai Jun 15, 2020

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



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>

parent d9d52398

sound/firewire/motu/motu-protocol-v3.c

+13 −3

Original line number	Diff line number	Diff line
		@@ -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;

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