From: zachberger <zach@zberger.com>
Date: Sat, 12 Sep 2026 19:23:24 +0000 (-0700)
Subject: USB-Audio: fix channel count for SSL 2+ Mk II
X-Git-Url: https://git.alsa-project.org/?a=commitdiff_plain;h=4367278c4546ae5132daabe8ece79f1a900f25a5;p=alsa-ucm-conf.git

USB-Audio: fix channel count for SSL 2+ Mk II

The "SSL 2+ Mk II" reports the same USB product ID (31e9:0009) as the
plain "SSL 2 Mk II", so the existing detection based on CardComponents
and bcdDevice cannot tell them apart. It has more physical I/O though:
6 playback channels and 8 capture channels, vs 4/4 for the plain model.

With the previous profile (DirectPlaybackChannels=4,
DirectCaptureChannels=4), WirePlumber rejects the whole card:

    spa.alsa: Error in ALSA UCM profile for _ucm0003.hw:II,0 (HiFi: Line2: sink): PlaybackChannels=4 < avail 6
    spa.alsa: Error in ALSA UCM profile for _ucm0003.hw:II,0 (HiFi: Mic2: source): CaptureChannels=4 < avail 8
    spa.alsa: Errors in ALSA UCM profile for card SSL 2+ Mk II

...and it shows up as "SSL 2+ Mk II [ALSA UCM error]" in wpctl/sound
pickers built on PipeWire.

Disambiguate using the USB product string (which does carry the "+"),
read via sys-card the same way bcdDevice already is, and set the
correct channel counts for the confirmed "SSL 2+ Mk II" case.

The If.chn4 gate in SSL2-HiFi.conf that builds the split Line1/Line2
output devices only matched DirectPlaybackChannels == "4" exactly.
Broaden it to match "4" or "6" so the "+" Mk II also gets routed
through the existing channel-splitting macros (which already use the
variable dynamically and needed no other change).

Tested against real "SSL 2+ Mk II" hardware (USB ID 31e9:0009,
bcdDevice 0116, 6 playback / 8 capture channels per USB descriptors).
Before: card flagged with [ALSA UCM error], no usable output. After:
clean profile, Line1/Line2 both work as separate stereo outputs,
Mic1/Mic2 both work as separate mono inputs.

Not extended to the non-Mk-II "SSL 2+" since that hardware wasn't
available to verify its channel counts also come out to 6/8.

Closes: https://github.com/alsa-project/alsa-ucm-conf/pull/854
Signed-off-by: zachberger <zach@zberger.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
---

diff --git a/ucm2/USB-Audio/SolidStateLabs/SSL2-HiFi.conf b/ucm2/USB-Audio/SolidStateLabs/SSL2-HiFi.conf
index 8e39b86..1fad5e8 100644
--- a/ucm2/USB-Audio/SolidStateLabs/SSL2-HiFi.conf
+++ b/ucm2/USB-Audio/SolidStateLabs/SSL2-HiFi.conf
@@ -15,9 +15,9 @@ Macro [
 
 If.chn4 {
 	Condition {
-		Type String
-		String1 "${var:DirectPlaybackChannels}"
-		String2 "4"
+		Type RegexMatch
+		String "${var:DirectPlaybackChannels}"
+		Regex "^(4|6)$"
 	}
 	True {
 		Macro [
diff --git a/ucm2/USB-Audio/SolidStateLabs/SSL2.conf b/ucm2/USB-Audio/SolidStateLabs/SSL2.conf
index 3df2fac..dfcbecb 100644
--- a/ucm2/USB-Audio/SolidStateLabs/SSL2.conf
+++ b/ucm2/USB-Audio/SolidStateLabs/SSL2.conf
@@ -23,6 +23,26 @@ If.fw {
 	True.Define.DirectCaptureChannels 2
 }
 
+# The "SSL 2+ Mk II" shares the same USB product ID (31e9:0009) as the
+# plain "SSL 2 Mk II", but has more physical I/O (6 playback / 8 capture
+# channels vs 4/4), which the USB descriptors above cannot distinguish.
+# Disambiguate using the USB product string instead, which does carry
+# the "+". (Only verified against "SSL 2+ Mk II" hardware; not assumed
+# to also apply to the non-Mk-II "SSL 2+".)
+If.ssl2plusmk2 {
+	Condition {
+		Type RegexMatch
+		String "${sys-card:device/../product}"
+		Regex "SSL 2\\+ Mk II"
+	}
+	True {
+		Define {
+			DirectPlaybackChannels 6
+			DirectCaptureChannels 8
+		}
+	}
+}
+
 SectionUseCase."HiFi" {
 	Comment "HiFi"
 	File "/USB-Audio/SolidStateLabs/SSL2-HiFi.conf"