From 82c9a87be0b5ce24e0a056cdb6ba7cbfa5255b1b Mon Sep 17 00:00:00 2001
From: Wu Fengguang <fengguang.wu@intel.com>
Date: Tue, 22 Nov 2011 16:46:23 +0800
Subject: [PATCH] --- yaml --- r: 275979 b: refs/heads/master c:
 a370fc62b9ad3f73abe2a721de6c03cdcce95b54 h: refs/heads/master i:   275977:
 8bf349bcd4a6673cb4b5ba0cc0bd62f879c8cc65   275975:
 7d7410ec0831ce083c42bda660c37eed7788147f v: v3

---
 [refs]                        |  2 +-
 trunk/sound/pci/hda/hda_eld.c | 28 +++++++++++++++++++---------
 2 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/[refs] b/[refs]
index e2bc38e503fa..3756ea4186c2 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: a29878553a9a7b4c06f93c7e383527cf014d4ceb
+refs/heads/master: a370fc62b9ad3f73abe2a721de6c03cdcce95b54
diff --git a/trunk/sound/pci/hda/hda_eld.c b/trunk/sound/pci/hda/hda_eld.c
index 7ae7578bdcc0..c1da422e085a 100644
--- a/trunk/sound/pci/hda/hda_eld.c
+++ b/trunk/sound/pci/hda/hda_eld.c
@@ -347,18 +347,28 @@ int snd_hdmi_get_eld(struct hdmi_eld *eld,
 
 	for (i = 0; i < size; i++) {
 		unsigned int val = hdmi_get_eld_data(codec, nid, i);
+		/*
+		 * Graphics driver might be writing to ELD buffer right now.
+		 * Just abort. The caller will repoll after a while.
+		 */
 		if (!(val & AC_ELDD_ELD_VALID)) {
-			if (!i) {
-				snd_printd(KERN_INFO
-					   "HDMI: invalid ELD data\n");
-				ret = -EINVAL;
-				goto error;
-			}
 			snd_printd(KERN_INFO
 				  "HDMI: invalid ELD data byte %d\n", i);
-			val = 0;
-		} else
-			val &= AC_ELDD_ELD_DATA;
+			ret = -EINVAL;
+			goto error;
+		}
+		val &= AC_ELDD_ELD_DATA;
+		/*
+		 * The first byte cannot be zero. This can happen on some DVI
+		 * connections. Some Intel chips may also need some 250ms delay
+		 * to return non-zero ELD data, even when the graphics driver
+		 * correctly writes ELD content before setting ELD_valid bit.
+		 */
+		if (!val && !i) {
+			snd_printdd(KERN_INFO "HDMI: 0 ELD data\n");
+			ret = -EINVAL;
+			goto error;
+		}
 		buf[i] = val;
 	}