conf: pcm: Set C-Media USB 7.1 sound card (ICUSBAUDIO7D) to six_channel for surround40

This 7.1 analog sound card identifies as the following:
0d8c:0102 C-Media Electronics, Inc. CM106 Like Sound Device (lsusb)
 1 [ICUSBAUDIO7D   ]: USB-Audio - ICUSBAUDIO7D (/proc/asound/cards)

It has the following four-channel analog stream layout:
  Interface 1
    Altset 3
    Format: S16_LE
    Channels: 4
    Endpoint: 6 OUT (ADAPTIVE)
    Rates: 44100, 48000
    Bits: 16
    Channel map: FL FR FC LFE
(/proc/asound/card1/stream0)

This layout makes it impossible to play audio to the surround (SL/SR)
speakers plugged into the "Surround" jack in 4 channel mode.  Instead,
set six_channel so that the six-channel layout will be used to access
those speakers:
  Interface 1
    Altset 4
    Format: S16_LE
    Channels: 6
    Endpoint: 6 OUT (ADAPTIVE)
    Rates: 44100, 48000
    Bits: 16
    Channel map: FL FR FC LFE SL SR

Tested with speaker-test -Dsurround40:CARD=ICUSBAUDIO7D,DEV=0 -c4

The speaker system that required surround40 in order to downmix LFE into
the front/rear mix is a Klipsch ProMedia v.2-400, which has 4 speakers
and a subwoofer with an internal crossover, connected via front and rear
stereo analog cables.

Closes: https://github.com/alsa-project/alsa-lib/pull/319
Signed-off-by: Ryan Underwood <nemesis@icequake.net>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

diff --git a/src/conf/cards/USB-Audio.conf b/src/conf/cards/USB-Audio.conf
index 839e61cb5ce04a778b12896ebaac21a6cf16bfc3..80631b2ef434d38cb4514c997da81e36c9e98dd3 100644 (file)
--- a/src/conf/cards/USB-Audio.conf
+++ b/src/conf/cards/USB-Audio.conf
@@ -27,6 +27,7 @@ USB-Audio.pcm.use_dmix {
 USB-Audio.pcm.surround40_type {
        "AudioPhile" two_stereo_devices
        "Audiophile USB (tm)" two_stereo_devices
+       "ICUSBAUDIO7D" six_channels
        "OmniStudio" two_stereo_devices
        "Quattro" two_stereo_devices
        "SB Audigy 2 NX" six_channels