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 8e39b8612eeb971c09d7e813bd7d111df6feb5a1..1fad5e89e5dd734a1ac5911dfe2645696187cab0 100644 (file)
--- 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 3df2fac507c27c606d30a09f3c26942612afb48a..dfcbecb7ef1301b4356b4c4b06567543a17929ef 100644 (file)
--- 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"