ALSA: dice: fix fallback from protocol extension into limited functionality

commit 3e2dc6bdb56893bc28257e482e1dbe5d39f313df upstream.

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: 58579c05 ("ALSA: dice: use extended protocol to detect available stream formats")
Signed-off-by: NTakashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20200113084630.14305-2-o-takashi@sakamocchi.jpSigned-off-by: NTakashi Iwai <tiwai@suse.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

sound/firewire/dice/dice-extension.c

@@ -159,10 +159,13 @@ 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;
 			}
 		}
+	}
 
 	section_addr = DICE_EXT_APP_SPACE + be32_to_cpu(pointers[12]) * 4;
 	err = detect_stream_formats(dice, section_addr);