12-19-2022, 02:06 PM
When I just copied your code, I got "no such file or directory":
But this produced an output:
pi@Moode:/proc/asound $ cat cards
0 [b1 ]: bcm2835_hdmi - bcm2835 HDMI 1
bcm2835 HDMI 1
1 [Headphones ]: bcm2835_headpho - bcm2835 Headphones
bcm2835 Headphones
2 [M2496 ]: USB-Audio - Musical Fidelity V90-DAC 24/96
Musical Fidelity Musical Fidelity V90-DAC 24/96 at usb-3f9 80000.usb-1.3, full s
then:
pi@Moode:/proc/asound $ amixer -c 2
pi@Moode:/proc/asound $
Since this produced no output I tired:
pi@Moode:/proc/asound/M2496 $ amixer
Simple mixer control 'HDMI',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback -10239 - 400
Mono: Playback -10239 [0%] [-99999.99dB] [on]
and:
pi@Moode:/proc/asound/M2496 $ amixer -c 2
pi@Moode:/proc/asound/M2496 $ amixer -c
amixer: option requires an argument -- 'c'
Invalid switch or option needs an argument.
Usage: amixer <options> [command]
Available options:
-h,--help this help
-c,--card N select the card
-D,--device N select the device, default 'default'
-d,--debug debug mode
-n,--nocheck do not perform range checking
-v,--version print version of this program
-q,--quiet be quiet
-i,--inactive show also inactive controls
-a,--abstract L select abstraction level (none or basic)
-s,--stdin Read and execute commands from stdin sequentially
-R,--raw-volume Use the raw value (default)
-M,--mapped-volume Use the mapped volume
Available commands:
scontrols show all mixer simple controls
scontents show contents of all mixer simple controls (default command)
sset sID P set contents for one mixer simple control
sget sID get contents for one mixer simple control
controls show all controls for given card
contents show contents of all controls for given card
cset cID P set control contents for one control
cget cID get control contents for one control
pi@Moode:/proc/asound/M2496 $
But this produced an output:
pi@Moode:/proc/asound $ cat cards
0 [b1 ]: bcm2835_hdmi - bcm2835 HDMI 1
bcm2835 HDMI 1
1 [Headphones ]: bcm2835_headpho - bcm2835 Headphones
bcm2835 Headphones
2 [M2496 ]: USB-Audio - Musical Fidelity V90-DAC 24/96
Musical Fidelity Musical Fidelity V90-DAC 24/96 at usb-3f9 80000.usb-1.3, full s
then:
pi@Moode:/proc/asound $ amixer -c 2
pi@Moode:/proc/asound $
Since this produced no output I tired:
pi@Moode:/proc/asound/M2496 $ amixer
Simple mixer control 'HDMI',0
Capabilities: pvolume pvolume-joined pswitch pswitch-joined
Playback channels: Mono
Limits: Playback -10239 - 400
Mono: Playback -10239 [0%] [-99999.99dB] [on]
and:
pi@Moode:/proc/asound/M2496 $ amixer -c 2
pi@Moode:/proc/asound/M2496 $ amixer -c
amixer: option requires an argument -- 'c'
Invalid switch or option needs an argument.
Usage: amixer <options> [command]
Available options:
-h,--help this help
-c,--card N select the card
-D,--device N select the device, default 'default'
-d,--debug debug mode
-n,--nocheck do not perform range checking
-v,--version print version of this program
-q,--quiet be quiet
-i,--inactive show also inactive controls
-a,--abstract L select abstraction level (none or basic)
-s,--stdin Read and execute commands from stdin sequentially
-R,--raw-volume Use the raw value (default)
-M,--mapped-volume Use the mapped volume
Available commands:
scontrols show all mixer simple controls
scontents show contents of all mixer simple controls (default command)
sset sID P set contents for one mixer simple control
sget sID get contents for one mixer simple control
controls show all controls for given card
contents show contents of all controls for given card
cset cID P set control contents for one control
cget cID get control contents for one control
pi@Moode:/proc/asound/M2496 $