[PATCH] ALSA: dice: fix regression for Lexicon I-ONIX FW810S

[Takashi Sakamoto]

For Lexicon I-ONIX FW810S, the call of ioctl(2) with
SNDRV_PCM_IOCTL_HW_PARAMS can returns -ETIMEDOUT. This is a regression due
to the commit 41319eb56e19 ("ALSA: dice: wait just for
NOTIFY_CLOCK_ACCEPTED after GLOBAL_CLOCK_SELECT operation"). The device
does not emit NOTIFY_CLOCK_ACCEPTED notification when accepting
GLOBAL_CLOCK_SELECT operation with the same parameters as current ones.

This commit fixes the regression. When receiving no notification, return
-ETIMEDOUT as long as operating for any change.

Fixes: 41319eb56e19 ("ALSA: dice: wait just for NOTIFY_CLOCK_ACCEPTED after GLOBAL_CLOCK_SELECT operation")
Cc: <stable at vger.kernel.org>
Signed-off-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>
---
 sound/firewire/dice/dice-stream.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/sound/firewire/dice/dice-stream.c b/sound/firewire/dice/dice-stream.c
index f99e00083141..4c677c8546c7 100644
--- a/sound/firewire/dice/dice-stream.c
+++ b/sound/firewire/dice/dice-stream.c
@@ -59,7 +59,7 @@ int snd_dice_stream_get_rate_mode(struct snd_dice *dice, unsigned int rate,
 
 static int select_clock(struct snd_dice *dice, unsigned int rate)
 {
-	__be32 reg;
+	__be32 reg, new;
 	u32 data;
 	int i;
 	int err;
@@ -83,15 +83,17 @@ static int select_clock(struct snd_dice *dice, unsigned int rate)
 	if (completion_done(&dice->clock_accepted))
 		reinit_completion(&dice->clock_accepted);
 
-	reg = cpu_to_be32(data);
+	new = cpu_to_be32(data);
 	err = snd_dice_transaction_write_global(dice, GLOBAL_CLOCK_SELECT,
-						&reg, sizeof(reg));
+						&new, sizeof(new));
 	if (err < 0)
 		return err;
 
 	if (wait_for_completion_timeout(&dice->clock_accepted,
-			msecs_to_jiffies(NOTIFICATION_TIMEOUT_MS)) == 0)
-		return -ETIMEDOUT;
+			msecs_to_jiffies(NOTIFICATION_TIMEOUT_MS)) == 0) {
+		if (reg != new)
+			return -ETIMEDOUT;
+	}
 
 	return 0;
 }
-- 
2.37.2