From ce9778b7a0272f7c7e5bc33f537380a5d2aed6c7 Mon Sep 17 00:00:00 2001
From: Kai-Heng Feng <kai.heng.feng@canonical.com>
Date: Thu, 2 Dec 2021 15:33:35 +0800
Subject: [PATCH] ALSA: hda/hdmi: Consider ELD is invalid when no SAD is present
Git-commit: ce9778b7a0272f7c7e5bc33f537380a5d2aed6c7
Patch-mainline: v5.17-rc1
References: bsc#1192354

There's a system that reports a bogus HDMI audio interface:
$ cat eld#2.0
monitor_present         1
eld_valid               1
monitor_name
connection_type         DisplayPort
eld_version             [0x2] CEA-861D or below
edid_version            [0x3] CEA-861-B, C or D
manufacture_id          0xe430
product_id              0x690
port_id                 0x0
support_hdcp            0
support_ai              0
audio_sync_delay        0
speakers                [0xffff] FL/FR LFE FC RL/RR RC FLC/FRC RLC/RRC FLW/FRW FLH/FRH TC FCH
sad_count               0

Since playing audio is not possible without SAD, also consider ELD is
invalid for this case.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Link: https://lore.kernel.org/r/20211202073338.1384768-1-kai.heng.feng@canonical.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

---
 sound/pci/hda/patch_hdmi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
index 65d2c5539919..33e5f1aa24f9 100644
--- a/sound/pci/hda/patch_hdmi.c
+++ b/sound/pci/hda/patch_hdmi.c
@@ -1535,7 +1535,7 @@ static void update_eld(struct hda_codec *codec,
 		}
 	}
 
-	if (!eld->eld_valid || eld->eld_size <= 0) {
+	if (!eld->eld_valid || eld->eld_size <= 0 || eld->info.sad_count <= 0) {
 		eld->eld_valid = false;
 		eld->eld_size = 0;
 	}
-- 
2.31.1