alsa-profiles: SB Audigy: stereo mixer paths

This is a follow-up to d5390c7, where we switched to the 'PCM' mixer controls
on Sound Blaster Audigy devices, since the ones we used before only work in the
stereo-to-all-speakers mirroring mode.

It turns out we do use that mode after all, but only in a couple of profiles.
Since returning those profiles to the default mixer path yields uneven volume
steps similar to #2934, we instead add a new mixer path just for that mode.

spa/plugins/alsa/mixer/paths/audigy-analog-output-mirror.conf

@@ -0,0 +1,56 @@
+; Mixer path for the Sound Blaster Audigy series, which uses the EMU10K2 DSP.
+; We target 'Wave' and other non-'PCM' controls as a special case for when
+; the device's stereo-to-all-speakers mirroring mode is in use.  (For example,
+; the Analog Stereo Output profile.)
+; https://docs.kernel.org/sound/cards/audigy-mixer.html
+;
+; See analog-output.conf.common for an explanation on the directives
+
+[General]
+priority = 99
+description-key = analog-output
+
+[Element Master]
+switch = mute
+volume = merge
+override-map.1 = all
+override-map.2 = all-left,all-right
+
+[Element Wave]
+volume = merge
+override-map.1 = all
+override-map.2 = all-left,all-right
+
+# The following elements also exist in analog-output.conf.  We list them here
+# instead of including that file, for ideal positioning of the Wave element:
+# Placing Wave below the Master element prevents Master from reaching its
+# loudest until the user raises the unified volume control to maximum.
+# (This should reduce the chance of a surprise speaker blow-out.)
+# Placing Wave above the per-channel elements yields even steps at low volume.
+
+[Element Front]
+volume = merge
+override-map.1 = all-front
+override-map.2 = front-left,front-right
+
+[Element Surround]
+volume = merge
+override-map.1 = all-rear
+override-map.2 = rear-left,rear-right
+
+[Element Side]
+volume = merge
+override-map.1 = all-side
+override-map.2 = side-left,side-right
+
+[Element Center]
+volume = merge
+override-map.1 = all-center
+override-map.2 = all-center,all-center
+
+[Element LFE]
+volume = merge
+override-map.1 = lfe
+override-map.2 = lfe,lfe
+
+.include analog-output.conf.common

spa/plugins/alsa/mixer/paths/audigy-analog-output.conf

@@ -1,7 +1,7 @@
 ; Mixer path for the Sound Blaster Audigy series, which uses the EMU10K2 DSP.
 ; We target 'PCM Front' and similarly named controls instead of 'Front' et al.
-; because the latter have no effect on volume, apparently intended for a
-; stereo-to-all-speakers mirroring mode that we do not use.
+; because the latter affect volume only in the device's stereo-to-all-speakers
+; mirroring mode, which is not used by most profiles.
 ; https://docs.kernel.org/sound/cards/audigy-mixer.html
 ;
 ; See analog-output.conf.common for an explanation on the directives

spa/plugins/alsa/mixer/profile-sets/audigy.conf

@@ -15,11 +15,11 @@
 
 ; Creative Sound Blaster Audigy product line
 ;
-; These are just copies of the mappings we find in default.conf, with
-; an analog mixer path targeting the Audigy driver's PCM outputs, and the
-; small change of making analog-stereo and analog-mono non-fallback mappings.
-; This is needed because these cards only support duplex profiles with mono
-; inputs, and in the default configuration, with stereo being a fallback
+; These are copies of the mappings we find in default.conf, but with analog
+; mixer paths targeting appropriate Audigy driver controls, and the small
+; change of making analog-stereo and analog-mono non-fallback mappings.
+; The latter is needed because these cards only support duplex profiles with
+; mono inputs, and in the default configuration, with stereo being a fallback
 ; mapping, the mono mapping is never tried.
 ;
 ; See default.conf for an explanation on the directives used here.
@@ -31,7 +31,7 @@ auto-profiles = yes
 [Mapping analog-stereo]
 device-strings = hw:%f
 channel-map = front-left,front-right
-paths-output = audigy-analog-output analog-output-lineout analog-output-speaker analog-output-headphones analog-output-headphones-2
+paths-output = audigy-analog-output-mirror analog-output-lineout analog-output-speaker analog-output-headphones analog-output-headphones-2
 paths-input = analog-input-front-mic analog-input-rear-mic analog-input-internal-mic analog-input-dock-mic analog-input analog-input-mic analog-input-linein analog-input-aux analog-input-video analog-input-tvtuner analog-input-fm analog-input-mic-line analog-input-headphone-mic analog-input-headset-mic
 priority = 1
 
@@ -39,7 +39,7 @@ priority = 1
 [Mapping analog-mono]
 device-strings = hw:%f
 channel-map = mono
-paths-output = audigy-analog-output analog-output-lineout analog-output-speaker analog-output-headphones analog-output-headphones-2 analog-output-mono
+paths-output = audigy-analog-output-mirror analog-output-lineout analog-output-speaker analog-output-headphones analog-output-headphones-2 analog-output-mono
 paths-input = analog-input-front-mic analog-input-rear-mic analog-input-internal-mic analog-input-dock-mic analog-input analog-input-mic analog-input-linein analog-input-aux analog-input-video analog-input-tvtuner analog-input-fm analog-input-mic-line analog-input-headset-mic
 priority = 1