From 01c2b4e708ef3bfb1b185b785f11d0b55702e990 Mon Sep 17 00:00:00 2001
From: Jaroslav Kysela <perex@perex.cz>
Date: Mon, 10 Mar 2025 17:11:49 +0100
Subject: [PATCH] USB-Audio: Improve support for Focusrite 4th Gen devices

There are 4 capture channels (additional ones for mixer monitor).

Closes: https://github.com/alsa-project/alsa-ucm-conf/issues/515
Closes: https://github.com/alsa-project/alsa-ucm-conf/pull/516
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
---
 .../USB-Audio/Focusrite/Scarlett-2i-HiFi.conf |   4 +-
 .../Focusrite/Scarlett-2i-gen4-HiFi.conf      | 124 ++++++++++++++++++
 ucm2/USB-Audio/Focusrite/Scarlett-2i.conf     |  40 +++++-
 3 files changed, 160 insertions(+), 8 deletions(-)
 create mode 100644 ucm2/USB-Audio/Focusrite/Scarlett-2i-gen4-HiFi.conf

diff --git a/ucm2/USB-Audio/Focusrite/Scarlett-2i-HiFi.conf b/ucm2/USB-Audio/Focusrite/Scarlett-2i-HiFi.conf
index 0484dc7..0fdd55c 100644
--- a/ucm2/USB-Audio/Focusrite/Scarlett-2i-HiFi.conf
+++ b/ucm2/USB-Audio/Focusrite/Scarlett-2i-HiFi.conf
@@ -14,7 +14,7 @@ Macro [
 	}
 ]
 
-If.2i4 {
+If.pch4 {
 	Condition {
 		Type String
 		String1 "${var:PlaybackChannels}"
@@ -65,7 +65,7 @@ SectionDevice."Line1" {
 	}
 }
 
-If.2i4 {
+If.line2 {
 	Condition {
 		Type String
 		String1 "${var:PlaybackChannels}"
diff --git a/ucm2/USB-Audio/Focusrite/Scarlett-2i-gen4-HiFi.conf b/ucm2/USB-Audio/Focusrite/Scarlett-2i-gen4-HiFi.conf
new file mode 100644
index 0000000..087239b
--- /dev/null
+++ b/ucm2/USB-Audio/Focusrite/Scarlett-2i-gen4-HiFi.conf
@@ -0,0 +1,124 @@
+Include.pcm_split.File "/common/pcm/split.conf"
+
+Macro [
+	{
+		SplitPCM {
+			Name "scarlett2i_mono_in"
+			Direction Capture
+			Format S32_LE
+			Channels 1
+			HWChannels 4
+			HWChannelPos0 MONO
+			HWChannelPos1 MONO
+		}
+	}
+	{
+		SplitPCM {
+			Name "scarlett2i_stereo_in"
+			Direction Capture
+			Format S32_LE
+			Channels 2
+			HWChannels 4
+			HWChannelPos0 MONO
+			HWChannelPos1 MONO
+			HWChannelPos2 FL
+			HWChannelPos3 FR
+		}
+	}
+]
+
+SectionDevice."Line1" {
+	Comment "${var:Playback1Name}"
+
+	Value {
+		PlaybackPriority 200
+		PlaybackPCM "hw:${CardId}"
+	}
+}
+
+SectionDevice."Mic1" {
+	Comment "${var:Capture1Name}"
+
+	Value {
+		CapturePriority 500
+	}
+	Macro.pcm_split.SplitPCMDevice {
+		Name "scarlett2i_mono_in"
+		Direction Capture
+		HWChannels 4
+		Channels 1
+		Channel0 0
+		ChannelPos0 MONO
+	}
+}
+
+SectionDevice."Mic2" {
+	Comment "${var:Capture2Name}"
+
+	Value {
+		CapturePriority 400
+	}
+	Macro.pcm_split.SplitPCMDevice {
+		Name "scarlett2i_mono_in"
+		Direction Capture
+		HWChannels 4
+		Channels 1
+		Channel0 1
+		ChannelPos0 MONO
+	}
+}
+
+SectionDevice."Line2" {
+	Comment "Monitor Input 3+4 (stereo)"
+
+	ConflictingDevice [
+		"Line3"
+		"Line4"
+	]
+
+	Value {
+		CapturePriority 300
+	}
+	Macro.pcm_split.SplitPCMDevice {
+		Name "scarlett2i_stereo_in"
+		Direction Capture
+		HWChannels 4
+		Channels 2
+		Channel0 2
+		Channel1 3
+		ChannelPos0 FL
+		ChannelPos1 FR
+	}
+}
+
+SectionDevice."Line3" {
+	Comment "Monitor Input 3"
+
+	Value {
+		CapturePriority 200
+	}
+	Macro.pcm_split.SplitPCMDevice {
+		Name "scarlett2i_mono_in"
+		Direction Capture
+		HWChannels 4
+		Channels 1
+		Channel0 2
+		ChannelPos0 MONO
+	}
+}
+
+SectionDevice."Line4" {
+	Comment "Monitor Input 4"
+
+	Value {
+		CapturePriority 100
+	}
+	Macro.pcm_split.SplitPCMDevice {
+		Name "scarlett2i_mono_in"
+		Direction Capture
+		HWChannels 4
+		Channels 1
+		Channel0 3
+		ChannelPos0 MONO
+	}
+}
diff --git a/ucm2/USB-Audio/Focusrite/Scarlett-2i.conf b/ucm2/USB-Audio/Focusrite/Scarlett-2i.conf
index fa03229..a27c7f9 100644
--- a/ucm2/USB-Audio/Focusrite/Scarlett-2i.conf
+++ b/ucm2/USB-Audio/Focusrite/Scarlett-2i.conf
@@ -1,13 +1,14 @@
 Define {
 	PlaybackChannels 2
-	DirectPlaybackChannels 2
-	DirectCaptureChannels 2
+	CaptureChannels 2
 	Model "2i2"
 	Playback1Name "Headphones / Line 1-2"
 	Playback2Name "Line 3-4"
 	Capture1Name "Input 1 Mic/Inst/Line"
 	Capture2Name "Input 2 Mic/Inst/Line"
+	CaptureMonitor ""
 	Generation "1st"
+	Profile "Scarlett-2i-HiFi"
 }
 
 If.solo {
@@ -55,20 +56,47 @@ If.gen3 {
 	True.Define.Generation "3rd"
 }
 
-If.gen4 {
+If.gen4-solo {
 	Condition {
 		Type RegexMatch
 		String "${CardComponents}"
-		Regex "USB1235:821[89]"
+		Regex "USB1235:8218"
+	}
+	True.Define {
+		Generation "4th"
+		Capture1Name "Input 1 Inst/Line"
+		Capture2Name "Input 2 Mic"
+		CaptureChannels 4
+		Profile "Scarlett-2i-gen4-HiFi"
+	}
+}
+
+If.gen4-2i2 {
+	Condition {
+		Type RegexMatch
+		String "${CardComponents}"
+		Regex "USB1235:8219"
+	}
+	True.Define {
+		Generation "4th"
+		CaptureChannels 4
+		Profile "Scarlett-2i-gen4-HiFi"
 	}
-	True.Define.Generation "4th"
 }
 
 Comment "Focusrite Scarlett ${var:Model} ${var:Generation} Gen"
 
 SectionUseCase."HiFi" {
 	Comment "Default"
-	File "/USB-Audio/Focusrite/Scarlett-2i-HiFi.conf"
+	File "/USB-Audio/Focusrite/${var:Profile}.conf"
+}
+
+If.dhw {
+	Condition { Type AlwaysTrue }
+	True.Define {
+		DirectPlaybackChannels "${var:PlaybackChannels}"
+		DirectCaptureChannels "${var:CaptureChannels}"
+	}
 }
 
 Include.dhw.File "/common/direct.conf"
-- 
2.47.1