From df621629d8fc1445cc7aeca15cd25e8ff6ff073f Mon Sep 17 00:00:00 2001
From: Matthias Reichl <hias@horus.com>
Date: Sat, 30 Apr 2022 16:28:45 +0200
Subject: conf: vc4-hdmi: use a proper hdmi pcm, fix broken default pcm

Userspace expects to see a HDMI pcm, so remove the somewhat broken
front and iec958 pcms and add a proper hdmi pcm instead.

The hdmi pcm supports HD/HBR audio passthrough and relays the IEC958
status bits on to the kernel driver so it can switch to HBR audio
packets if needed. The control hook is marked optional because kernels
before 5.14 didn't expose the IEC958 controls.

The default pcm never worked as dmix doesn't support the iec958 format.
So drop dmix, only use plug and softvol, and use the hdmi pcm for
iec958 formatting.

Fixes: https://github.com/alsa-project/alsa-lib/issues/229
Link: https://lore.kernel.org/alsa-devel/20220430142845.229409-1-hias@horus.com/
Signed-off-by: Matthias Reichl <hias@horus.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
---
 src/conf/cards/vc4-hdmi.conf | 78 +++++++++++++++++++++++++++-----------------
 1 file changed, 48 insertions(+), 30 deletions(-)

diff --git a/src/conf/cards/vc4-hdmi.conf b/src/conf/cards/vc4-hdmi.conf
index 027804a1..af87b3a8 100644
--- a/src/conf/cards/vc4-hdmi.conf
+++ b/src/conf/cards/vc4-hdmi.conf
@@ -3,36 +3,9 @@
 # subframe conversion
 #
 
-<confdir:pcm/front.conf>
+<confdir:pcm/hdmi.conf>
 
-vc4-hdmi.pcm.front.0 {
-	@args [ CARD ]
-	@args.CARD {
-		type string
-	}
-	type hw
-	card $CARD
-}
-
-# default with dmix
-vc4-hdmi.pcm.default {
-	@args [ CARD ]
-	@args.CARD {
-		type string
-	}
-	type asym
-	playback.pcm {
-		type plug
-		slave.pcm {
-			@func concat
-			strings [ "dmix:" $CARD ]
-		}
-	}
-}
-
-<confdir:pcm/iec958.conf>
-
-vc4-hdmi.pcm.iec958.0 {
+vc4-hdmi.pcm.hdmi.0 {
 	@args [ CARD AES0 AES1 AES2 AES3 ]
 	@args.CARD {
 		type string
@@ -53,12 +26,57 @@ vc4-hdmi.pcm.iec958.0 {
 	slave {
 		format IEC958_SUBFRAME_LE
 		pcm {
-			type plug
+			type hooks
 			slave.pcm {
 				type hw
 				card $CARD
+				device 0
+			}
+			hooks.0 {
+				type ctl_elems
+				hook_args [
+				{
+					name "IEC958 Playback Default"
+					interface PCM
+					optional true
+					lock true
+					preserve true
+					value [ $AES0 $AES1 $AES2 $AES3 ]
+				}
+				]
 			}
 		}
 	}
 	status [ $AES0 $AES1 $AES2 $AES3 ]
+	hdmi_mode true
+}
+
+# default with plug and softvol
+vc4-hdmi.pcm.default {
+	@args [ CARD ]
+	@args.CARD {
+		type string
+	}
+	type asym
+	playback.pcm {
+		type plug
+		slave.pcm {
+			type softvol
+			slave.pcm {
+				@func concat
+				strings [
+					"cards.vc4-hdmi.pcm.hdmi.0:"
+					"CARD=" $CARD ","
+					"AES0=0x04,"	# IEC958_AES0_CON_NOT_COPYRIGHT | IEC958_AES0_CON_EMPHASIS_NONE
+					"AES1=0x82,"	# IEC958_AES1_CON_ORIGINAL | IEC958_AES1_CON_PCM_CODER
+					"AES2=0x00,"	# IEC958_AES2_CON_SOURCE_UNSPEC | IEC958_AES2_CON_CHANNEL_UNSPEC
+					"AES3=0x01"	# IEC958_AES3_CON_FS_NOTID (iec958 plugin will fill in actual rate)
+				]
+			}
+			control {
+				name "PCM Playback Volume"
+				card $CARD
+			}
+		}
+	}
 }
-- 
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