From 3e2dc6bdb56893bc28257e482e1dbe5d39f313df Mon Sep 17 00:00:00 2001
From: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Date: Mon, 13 Jan 2020 17:46:28 +0900
Subject: [PATCH] ALSA: dice: fix fallback from protocol extension into limited
 functionality

At failure of attempt to detect protocol extension, ALSA dice driver
should be fallback to limited functionality. However it's not.

This commit fixes it.

Cc: <stable@vger.kernel.org> # v4.18+
Fixes: 58579c056c1c9 ("ALSA: dice: use extended protocol to detect available stream formats")
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20200113084630.14305-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/firewire/dice/dice-extension.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/sound/firewire/dice/dice-extension.c b/sound/firewire/dice/dice-extension.c
index a63fcbc875ad..02f4a8318e38 100644
--- a/sound/firewire/dice/dice-extension.c
+++ b/sound/firewire/dice/dice-extension.c
@@ -159,8 +159,11 @@ int snd_dice_detect_extension_formats(struct snd_dice *dice)
 		int j;
 
 		for (j = i + 1; j < 9; ++j) {
-			if (pointers[i * 2] == pointers[j * 2])
+			if (pointers[i * 2] == pointers[j * 2]) {
+				// Fallback to limited functionality.
+				err = -ENXIO;
 				goto end;
+			}
 		}
 	}