Hi,

I have written a small (proof of concept) program that is providing audio on all my channels on the audio. What I have noticed is that the "Speaker" channel gets muted every time. I don't know how or by who?

When I change with alsamixer the mute then after less then 5 sec it get muted. How can I debug who is muting my 'Speaker' channel.

Here is some output.

[root@localhost ~]# amixer -c 0 Simple mixer control 'Headphone',0 Capabilities: pvolume pswitch Playback channels: Front Left - Front Right Limits: Playback 0 - 127 Mono: Front Left: Playback 75 [59%] [-20.00dB] [on] Front Right: Playback 75 [59%] [-20.00dB] [on] Simple mixer control 'Headphone SZCMode',0 Capabilities: penum Items: 'Immediate' 'Zero Cross' 'Soft Ramp' 'Soft Ramp on Zero Cross' Item0: 'Soft Ramp' Simple mixer control 'Line',0 Capabilities: cvolume cswitch Capture channels: Front Left - Front Right Limits: Capture 0 - 63 Front Left: Capture 51 [81%] [0.00dB] [off] Front Right: Capture 51 [81%] [0.00dB] [off] Simple mixer control 'Line Input',0 Capabilities: cvolume Capture channels: Front Left - Front Right Limits: Capture 0 - 3 Front Left: Capture 0 [0%] [0.00dB] Front Right: Capture 0 [0%] [0.00dB] Simple mixer control 'Line-In PGA Mode',0 Capabilities: cenum Items: 'Differential' 'Single-ended' Item0: 'Differential' Simple mixer control 'Line-Out',0 Capabilities: pvolume pswitch Playback channels: Front Left - Front Right Limits: Playback 0 - 127 Mono: Front Left: Playback 115 [91%] [0.00dB] [on] Front Right: Playback 115 [91%] [0.00dB] [on] Simple mixer control 'Line-In SZCMode',0 Capabilities: cenum Items: 'Immediate' 'Digital Immediate, Analog Zero Cross' 'Digital and Analog Soft Ramp' 'Digital Soft Ramp, Analog Zero Cross' Item0: 'Digital and Analog Soft Ramp' Simple mixer control 'Line-Out SZCMode',0 Capabilities: penum Items: 'Immediate' 'Zero Cross' 'Soft Ramp' 'Soft Ramp on Zero Cross' Item0: 'Soft Ramp' Simple mixer control 'Mic',0 Capabilities: cvolume cswitch Capture channels: Front Left - Front Right Limits: Capture 0 - 63 Front Left: Capture 51 [81%] [0.00dB] [off] Front Right: Capture 51 [81%] [0.00dB] [off] Simple mixer control 'Mic Input',0 Capabilities: cvolume Capture channels: Front Left - Front Right Limits: Capture 0 - 3 Front Left: Capture 0 [0%] [0.00dB] Front Right: Capture 0 [0%] [0.00dB] Simple mixer control 'Mic PGA Mode',0 Capabilities: cenum Items: 'Differential' 'Single-ended' Item0: 'Differential' Simple mixer control 'Mic SZCMode',0 Capabilities: cenum Items: 'Immediate' 'Digital Immediate, Analog Zero Cross' 'Digital and Analog Soft Ramp' 'Digital Soft Ramp, Analog Zero Cross' Item0: 'Digital and Analog Soft Ramp' Simple mixer control 'IEC958',0 Capabilities: pswitch pswitch-joined cswitch cswitch-joined Playback channels: Mono Capture channels: Mono Mono: Playback [off] Capture [off] Simple mixer control 'IEC958 Default PCM',0 Capabilities: pswitch pswitch-joined Playback channels: Mono Mono: Playback [on] Simple mixer control 'Analog In',0 Capabilities: cswitch cswitch-joined cswitch-exclusive Capture exclusive group: 0 Capture channels: Mono Mono: Capture [on] Simple mixer control 'Analog In',1 Capabilities: cswitch cswitch-joined cswitch-exclusive Capture exclusive group: 0 Capture channels: Mono Mono: Capture [on] Simple mixer control 'Digital Input 1',0 Capabilities: cvolume Capture channels: Front Left - Front Right Limits: Capture 0 - 2 Front Left: Capture 0 [0%] [0.00dB] Front Right: Capture 0 [0%] [0.00dB] Simple mixer control 'Digital Input 2',0 Capabilities: cvolume Capture channels: Front Left - Front Right Limits: Capture 0 - 2 Front Left: Capture 0 [0%] [0.00dB] Front Right: Capture 0 [0%] [0.00dB] Simple mixer control 'Digital Mic',0 Capabilities: cswitch cswitch-joined cswitch-exclusive Capture exclusive group: 0 Capture channels: Mono Mono: Capture [off] Simple mixer control 'Digital Mic',1 Capabilities: cswitch cswitch-joined cswitch-exclusive Capture exclusive group: 0 Capture channels: Mono Mono: Capture [off] Simple mixer control 'Speakers',0 Capabilities: pvolume pswitch Playback channels: Front Left - Front Right Limits: Playback 0 - 127 Mono: Front Left: Playback 100 [79%] [-7.50dB] [off] Front Right: Playback 100 [79%] [-7.50dB] [off] Simple mixer control 'Speakers SZCMode',0 Capabilities: penum Items: 'Immediate' 'Zero Cross' 'Soft Ramp' 'Soft Ramp on Zero Cross' Item0: 'Soft Ramp' [root@localhost ~]#

No I unmute the "Speaker" channel:

[root@localhost ~]# amixer set -c 0 Speakers unmute; date Simple mixer control 'Speakers',0 Capabilities: pvolume pswitch Playback channels: Front Left - Front Right Limits: Playback 0 - 127 Mono: Front Left: Playback 100 [79%] [-7.50dB] [on] Front Right: Playback 100 [79%] [-7.50dB] [on] Thu May 14 16:20:57 EDT 2009 [root@localhost ~]# amixer get -c 0 Speakers; date Simple mixer control 'Speakers',0 Capabilities: pvolume pswitch Playback channels: Front Left - Front Right Limits: Playback 0 - 127 Mono: Front Left: Playback 100 [79%] [-7.50dB] [on] Front Right: Playback 100 [79%] [-7.50dB] [on] Thu May 14 16:20:58 EDT 2009 [root@localhost ~]# amixer get -c 0 Speakers; date Simple mixer control 'Speakers',0 Capabilities: pvolume pswitch Playback channels: Front Left - Front Right Limits: Playback 0 - 127 Mono: Front Left: Playback 100 [79%] [-7.50dB] [off] Front Right: Playback 100 [79%] [-7.50dB] [off] Thu May 14 16:21:00 EDT 2009 [root@localhost ~]# amixer get -c 0 Speakers; date Simple mixer control 'Speakers',0 Capabilities: pvolume pswitch Playback channels: Front Left - Front Right Limits: Playback 0 - 127 Mono: Front Left: Playback 100 [79%] [-7.50dB] [off] Front Right: Playback 100 [79%] [-7.50dB] [off] Thu May 14 16:21:01 EDT 2009 [root@localhost ~]#