From 2da765f1b8aaca8dfddcc6e767806a3ff56b3e2b Mon Sep 17 00:00:00 2001
From: Mark Brown <broonie@opensource.wolfsonmicro.com>
Date: Wed, 14 Jul 2010 16:14:33 +0100
Subject: [PATCH] --- yaml --- r: 206604 b: refs/heads/master c:
 5164d74d74447895aaa31c094a1b9e666acaa656 h: refs/heads/master v: v3

---
 [refs]                     |  2 +-
 trunk/sound/soc/soc-core.c | 22 +++++++++++++++++-----
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/[refs] b/[refs]
index 4fbdb81ddb61..8b90cad432b8 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 03b0dc02cf54a79d6bc2f49c0005bc07db5120a4
+refs/heads/master: 5164d74d74447895aaa31c094a1b9e666acaa656
diff --git a/trunk/sound/soc/soc-core.c b/trunk/sound/soc/soc-core.c
index 8b79d90efdc1..5299932db0b6 100644
--- a/trunk/sound/soc/soc-core.c
+++ b/trunk/sound/soc/soc-core.c
@@ -84,7 +84,7 @@ static int run_delayed_work(struct delayed_work *dwork)
 /* codec register dump */
 static ssize_t soc_codec_reg_show(struct snd_soc_codec *codec, char *buf)
 {
-	int i, step = 1, count = 0;
+	int ret, i, step = 1, count = 0;
 
 	if (!codec->reg_cache_size)
 		return 0;
@@ -101,12 +101,24 @@ static ssize_t soc_codec_reg_show(struct snd_soc_codec *codec, char *buf)
 		if (count >= PAGE_SIZE - 1)
 			break;
 
-		if (codec->display_register)
+		if (codec->display_register) {
 			count += codec->display_register(codec, buf + count,
 							 PAGE_SIZE - count, i);
-		else
-			count += snprintf(buf + count, PAGE_SIZE - count,
-					  "%4x", codec->read(codec, i));
+		} else {
+			/* If the read fails it's almost certainly due to
+			 * the register being volatile and the device being
+			 * powered off.
+			 */
+			ret = codec->read(codec, i);
+			if (ret >= 0)
+				count += snprintf(buf + count,
+						  PAGE_SIZE - count,
+						  "%4x", ret);
+			else
+				count += snprintf(buf + count,
+						  PAGE_SIZE - count,
+						  "<no data: %d>", ret);
+		}
 
 		if (count >= PAGE_SIZE - 1)
 			break;