I explicitly set all the configurations that appear relevant on I2S1 and I2S4.
No sound is generated from I2S1
amixer -c 1 sset 'I2S1 Channels' 2
amixer -c 1 sset 'I2S1 Mux' 'I2S4'
amixer -c 1 sset 'I2S1 Sample Rate' 48000
amixer -c 1 sset 'I2S1 codec bit format' 16
amixer -c 1 sset 'I2S1 codec frame mode' 'i2s'
amixer -c 1 sset 'I2S1 codec master mode' 'cbs-cfs'
amixer -c 1 sset 'I2S1 input bit format' 16
amixer -c 1 sset 'I2S4 Channels' 2
amixer -c 1 sset 'I2S4 Sample Rate' 48000
amixer -c 1 sset 'I2S4 codec bit format' 16
amixer -c 1 sset 'I2S4 codec frame mode' 'i2s'
amixer -c 1 sset 'I2S4 codec master mode' 'cbm-cfm'
amixer -c 1 sset 'I2S4 input bit format' 16
Dumping the entire amixer configuration for those two ports
Simple mixer control 'I2S1 BCLK Ratio',0
Capabilities: volume volume-joined
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 2147483647
Mono: 1 [0%]
Simple mixer control 'I2S1 Capture mono to stereo conv',0
Capabilities: enum
Items: 'None' 'ZERO' 'COPY'
Item0: 'None'
Simple mixer control 'I2S1 Capture stereo to mono conv',0
Capabilities: enum
Items: 'None' 'CH0' 'CH1' 'AVG'
Item0: 'None'
Simple mixer control 'I2S1 Channels',0
Capabilities: volume volume-joined
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 16
Mono: 2 [12%]
Simple mixer control 'I2S1 Loopback',0
Capabilities: pswitch pswitch-joined
Playback channels: Mono
Mono: Playback [off]
Simple mixer control 'I2S1 Mux',0
Capabilities: enum
Items: 'None' 'ADMAIF1' 'ADMAIF2' 'ADMAIF3' 'ADMAIF4' 'ADMAIF5' 'ADMAIF6' 'ADMAIF7' 'ADMAIF8' 'ADMAIF9' 'ADMAIF10' 'ADMAIF11' 'ADMAIF12' 'ADMAIF13' 'ADMAIF14' 'ADMAIF15' 'ADMAIF16' 'I2S1' 'I2S2' 'I2S3' 'I2S4' 'I2S5' 'I2S6' 'SFC1' 'SFC2' 'SFC3' 'SFC4' 'MIXER1-1' 'MIXER1-2' 'MIXER1-3' 'MIXER1-4' 'MIXER1-5' 'AMX1' 'AMX2' 'AMX3' 'AMX4' 'ARAD1' 'AFC1' 'AFC2' 'AFC3' 'AFC4' 'AFC5' 'AFC6' 'OPE1' 'SPKPROT1' 'MVC1' 'MVC2' 'IQC1-1' 'IQC1-2' 'IQC2-1' 'IQC2-2' 'DMIC1' 'DMIC2' 'DMIC3' 'DMIC4' 'ADX1-1' 'ADX1-2' 'ADX1-3' 'ADX1-4' 'ADX2-1' 'ADX2-2' 'ADX2-3' 'ADX2-4' 'ADX3-1' 'ADX3-2' 'ADX3-3' 'ADX3-4' 'ADX4-1' 'ADX4-2' 'ADX4-3' 'ADX4-4' 'ADMAIF17' 'ADMAIF18' 'ADMAIF19' 'ADMAIF20' 'ASRC1-1' 'ASRC1-2' 'ASRC1-3' 'ASRC1-4' 'ASRC1-5' 'ASRC1-6'
Item0: 'I2S4'
Simple mixer control 'I2S1 Playback FIFO threshold',0
Capabilities: volume volume-joined
Playback channels: Mono
Capture channels: Mono
Limits: 270582939648 - 63
Mono: 270582939714 [0%]
Simple mixer control 'I2S1 Playback mono to stereo conv',0
Capabilities: enum
Items: 'None' 'ZERO' 'COPY'
Item0: 'None'
Simple mixer control 'I2S1 Playback stereo to mono conv',0
Capabilities: enum
Items: 'None' 'CH0' 'CH1' 'AVG'
Item0: 'None'
Simple mixer control 'I2S1 Sample Rate',0
Capabilities: volume volume-joined
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 192000
Mono: 48000 [25%]
Simple mixer control 'I2S1 codec bit format',0
Capabilities: enum
Items: 'None' '16' '32'
Item0: '16'
Simple mixer control 'I2S1 codec frame mode',0
Capabilities: enum
Items: 'None' 'i2s' 'right-j' 'left-j' 'dsp-a' 'dsp-b'
Item0: 'i2s'
Simple mixer control 'I2S1 codec master mode',0
Capabilities: enum
Items: 'None' 'cbm-cfm' 'cbs-cfs'
Item0: 'cbs-cfs'
Simple mixer control 'I2S1 fsync width',0
Capabilities: volume volume-joined
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 255
Mono: 31 [12%]
Simple mixer control 'I2S1 input bit format',0
Capabilities: enum
Items: 'None' '16' '32'
Item0: '16'
Simple mixer control 'I2S4 BCLK Ratio',0
Capabilities: volume volume-joined
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 2147483647
Mono: 1 [0%]
Simple mixer control 'I2S4 Capture mono to stereo conv',0
Capabilities: enum
Items: 'None' 'ZERO' 'COPY'
Item0: 'None'
Simple mixer control 'I2S4 Capture stereo to mono conv',0
Capabilities: enum
Items: 'None' 'CH0' 'CH1' 'AVG'
Item0: 'None'
Simple mixer control 'I2S4 Channels',0
Capabilities: volume volume-joined
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 16
Mono: 2 [12%]
Simple mixer control 'I2S4 Loopback',0
Capabilities: pswitch pswitch-joined
Playback channels: Mono
Mono: Playback [off]
Simple mixer control 'I2S4 Mux',0
Capabilities: enum
Items: 'None' 'ADMAIF1' 'ADMAIF2' 'ADMAIF3' 'ADMAIF4' 'ADMAIF5' 'ADMAIF6' 'ADMAIF7' 'ADMAIF8' 'ADMAIF9' 'ADMAIF10' 'ADMAIF11' 'ADMAIF12' 'ADMAIF13' 'ADMAIF14' 'ADMAIF15' 'ADMAIF16' 'I2S1' 'I2S2' 'I2S3' 'I2S4' 'I2S5' 'I2S6' 'SFC1' 'SFC2' 'SFC3' 'SFC4' 'MIXER1-1' 'MIXER1-2' 'MIXER1-3' 'MIXER1-4' 'MIXER1-5' 'AMX1' 'AMX2' 'AMX3' 'AMX4' 'ARAD1' 'AFC1' 'AFC2' 'AFC3' 'AFC4' 'AFC5' 'AFC6' 'OPE1' 'SPKPROT1' 'MVC1' 'MVC2' 'IQC1-1' 'IQC1-2' 'IQC2-1' 'IQC2-2' 'DMIC1' 'DMIC2' 'DMIC3' 'DMIC4' 'ADX1-1' 'ADX1-2' 'ADX1-3' 'ADX1-4' 'ADX2-1' 'ADX2-2' 'ADX2-3' 'ADX2-4' 'ADX3-1' 'ADX3-2' 'ADX3-3' 'ADX3-4' 'ADX4-1' 'ADX4-2' 'ADX4-3' 'ADX4-4' 'ADMAIF17' 'ADMAIF18' 'ADMAIF19' 'ADMAIF20' 'ASRC1-1' 'ASRC1-2' 'ASRC1-3' 'ASRC1-4' 'ASRC1-5' 'ASRC1-6'
Item0: 'None'
Simple mixer control 'I2S4 Playback FIFO threshold',0
Capabilities: volume volume-joined
Playback channels: Mono
Capture channels: Mono
Limits: 270582939648 - 63
Mono: 270582939714 [0%]
Simple mixer control 'I2S4 Playback mono to stereo conv',0
Capabilities: enum
Items: 'None' 'ZERO' 'COPY'
Item0: 'None'
Simple mixer control 'I2S4 Playback stereo to mono conv',0
Capabilities: enum
Items: 'None' 'CH0' 'CH1' 'AVG'
Item0: 'None'
Simple mixer control 'I2S4 Sample Rate',0
Capabilities: volume volume-joined
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 192000
Mono: 48000 [25%]
Simple mixer control 'I2S4 codec bit format',0
Capabilities: enum
Items: 'None' '16' '32'
Item0: '16'
Simple mixer control 'I2S4 codec frame mode',0
Capabilities: enum
Items: 'None' 'i2s' 'right-j' 'left-j' 'dsp-a' 'dsp-b'
Item0: 'i2s'
Simple mixer control 'I2S4 codec master mode',0
Capabilities: enum
Items: 'None' 'cbm-cfm' 'cbs-cfs'
Item0: 'cbm-cfm'
Simple mixer control 'I2S4 fsync width',0
Capabilities: volume volume-joined
Playback channels: Mono
Capture channels: Mono
Limits: 0 - 255
Mono: 31 [12%]
Simple mixer control 'I2S4 input bit format',0
Capabilities: enum
Items: 'None' '16' '32'
Item0: '16'
The registers are then
cat /sys/kernel/debug/regmap/tegra210-i2s.0/registers
00: 00000001
04: 00000000
08: 00000000
0c: 00000005
10: 0000000c
14: 00000003
18: 00000000
1c: 00000000
20: 03113300
24: 00000100
28: 00000000
2c: 00000000
30: 00000000
34: 00000000
38: 00000000
3c: 00000000
40: 00000000
44: 00000000
48: 00000000
4c: 00000002
50: 00000000
54: 00000003
58: 00000000
5c: 00000000
60: 00007700
64: 00000100
68: 00000000
6c: 00000000
70: 00000000
74: 00000000
78: 00000000
7c: 00000000
80: 00000001
84: 00000000
88: 00000001
8c: 00000000
90: 00000c00
94: 00000000
98: 00000000
9c: 00000000
a0: 1f000403
a4: 0000000f
a8: 00000000
ac: 00000000
b0: 00000000
cat /sys/kernel/debug/regmap/tegra210-i2s.3/registers
00: 00000000
04: 00000000
08: 00000000
0c: 00000002
10: 00000000
14: 00000003
18: 00000000
1c: 00000000
20: 00007700
24: 00000100
28: 00000000
2c: 00000000
30: 00000000
34: 00000000
38: 00000000
3c: 00000000
40: 00000001
44: 00000000
48: 00000000
4c: 00000001
50: 0000000e
54: 00000003
58: 00000000
5c: 00000000
60: 00113300
64: 00000100
68: 00000000
6c: 00000000
70: 00000000
74: 00000000
78: 00000000
7c: 00000000
80: 00000001
84: 00000000
88: 00000001
8c: 00000000
90: 0000000e
94: 00000000
98: 00000000
9c: 00000000
a0: 1f000003
a4: 0000000f
a8: 00000000
ac: 00000000
b0: 00000000
This command does generate the expected sound
gst-launch-1.0 alsasrc device=hw:CARD=tegrasndt186ref,DEV=3 ! 'audio/x-raw, format=S16LE, rate=48000, channels=2' ! queue ! alsasink device=hw:1,0
The registers are unchanged from above