How to save volume set by amixer ?

peng cheng

platform: DM8168, DVRRDK3.5.

I recently encountered a strange problem。I used cmd amixer to set the board output volume 。

root@dm816x:/opt/dvr_rdk/ti816x/bin# amixer  -c 0 cget numid=10
numid=10,iface=MIXER,name='Playback Volume'
  ; type=INTEGER,access=rw---R--,values=2,min=0,max=255,step=0
  : values=255,255
  | dBscale-min=-127.00dB,step=0.50dB,mute=1
root@dm816x:/opt/dvr_rdk/ti816x/bin# amixer  -c 0 cset numid=10 100
numid=10,iface=MIXER,name='Playback Volume'
  ; type=INTEGER,access=rw---R--,values=2,min=0,max=255,step=0
  : values=100,100
  | dBscale-min=-127.00dB,step=0.50dB,mute=1
root@dm816x:/opt/dvr_rdk/ti816x/bin# amixer  -c 0 cget numid=10
numid=10,iface=MIXER,name='Playback Volume'
  ; type=INTEGER,access=rw---R--,values=2,min=0,max=255,step=0
  : values=100,100
  | dBscale-min=-127.00dB,step=0.50dB,mute=1

and now , the volume have been set to "100,100". Then I used program "aplay" to play a sound ，but it‘s too load. So i check the volume again ,then I

found the volume was modefied to "255,255" again。

root@dm816x:/opt/dvr_rdk/ti816x/bin# aplay moto.wav -D default:CARD=SOUND0
Playing WAVE 'moto.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo
root@dm816x:/opt/dvr_rdk/ti816x/bin# amixer  -c 0 cget numid=10
numid=10,iface=MIXER,name='Playback Volume'
  ; type=INTEGER,access=rw---R--,values=2,min=0,max=255,step=0
  : values=255,255
  | dBscale-min=-127.00dB,step=0.50dB,mute=1

I don't how to solve this problem. I google this issue , but have no use.

Anyone can give me help? thanks.

over 10 years ago

0 Pavel Botev over 10 years ago

TI__Guru**** 170625 points

Hi Peng,

Have you check the below wiki pages?

processors.wiki.ti.com/.../ALSA
processors.wiki.ti.com/.../TI81XX_PSP_AUDIO_Driver_User_Guide

BR
Pavel

0 peng cheng over 10 years ago in reply to Pavel Botev

Prodigy 130 points

Hi，Pavel， thank you for your reply。
I checked this 2 pages , but i still can not solve this problem.
I write a program: alsa_play with alsa lib. I can used amixer to set the volume to 100 successfully , but when i played the moto.wav by alsa_play or aplay, the volume was modified to 255 again. And now the problem is , how can I set the audio to the local that I do not need to re set up every time when i play an audio.
Best regards.

0 Pavel Botev over 10 years ago in reply to peng cheng

TI__Guru**** 170625 points

Peng,

I have checked this on my side (EZSDK on DM816x TI EVM) and it works fine.

I am doing the below steps:

1. Check which is my playback volume id:

root@dm816x-evm:~# amixer controls
numid=1,iface=MIXER,name='PCM Playback Volume'
numid=22,iface=MIXER,name='Line DAC Playback Volume'
numid=20,iface=MIXER,name='Line Line2 Bypass Volume'
numid=21,iface=MIXER,name='Line PGA Bypass Volume'
numid=32,iface=MIXER,name='Line Playback Switch'
numid=25,iface=MIXER,name='Mono DAC Playback Volume'
..........

Mine is numid 1

2. Check the default settings:

root@dm816x-evm:~# amixer cget numid=1
numid=1,iface=MIXER,name='PCM Playback Volume'
; type=INTEGER,access=rw---R--,values=2,min=0,max=127,step=0
: values=87,87
| dBscale-min=-63.50dB,step=0.50dB,mute=0

3. Play a wav file and hear the sound:

root@dm816x-evm:~# aplay WaveData.wav
Playing WAVE 'WaveData.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo

4. Set/increase the playback volume from default/87 to 110:

root@dm816x-evm:~# amixer cset numid=1 110
numid=1,iface=MIXER,name='PCM Playback Volume'
; type=INTEGER,access=rw---R--,values=2,min=0,max=127,step=0
: values=110,110
| dBscale-min=-63.50dB,step=0.50dB,mute=0

5. Check the new settings:

root@dm816x-evm:~# amixer cget numid=1
numid=1,iface=MIXER,name='PCM Playback Volume'
; type=INTEGER,access=rw---R--,values=2,min=0,max=127,step=0
: values=110,110
| dBscale-min=-63.50dB,step=0.50dB,mute=0

6. Play a wav file and hear the sound:

root@dm816x-evm:~# aplay WaveData.wav
Playing WAVE 'WaveData.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo

The sound/volume is increased.

7. Set/decrease the playback volume from 110 to 20:

root@dm816x-evm:~# amixer cset numid=1 20
numid=1,iface=MIXER,name='PCM Playback Volume'
; type=INTEGER,access=rw---R--,values=2,min=0,max=127,step=0
: values=20,20
| dBscale-min=-63.50dB,step=0.50dB,mute=0

8. Check new settings are valid:

root@dm816x-evm:~# amixer cget numid=1
numid=1,iface=MIXER,name='PCM Playback Volume'
; type=INTEGER,access=rw---R--,values=2,min=0,max=127,step=0
: values=20,20
| dBscale-min=-63.50dB,step=0.50dB,mute=0

9. Play a wav file and hear the sound:

root@dm816x-evm:~# aplay WaveData.wav
Playing WAVE 'WaveData.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo

The sound/volume is decreased.

Can you try that flow on your side?

BR
Pavel

0 peng cheng over 10 years ago in reply to Pavel Botev

Prodigy 130 points

Hi Pavel， I tried as you said. The problem is still there. I consider to change a new file system to try again.

0 Pavel Botev over 10 years ago in reply to peng cheng

TI__Guru**** 170625 points

Peng,

Try also with the latest DM816x DVR RDK linux kernel code base, available at the below location:
http://arago-project.org/git/projects/?p=linux-dvr-rdk-dm81xx.git;a=shortlog;h=refs/heads/dvrrdk_kernel_int_branch

Regarding rootfs, the one I use is from DM816x EZSDK:
ti-ezsdk_dm816x-evm_5_05_02_00/filesystem/ezsdk-dm816x-evm-rootfs.tar.gz

You can explore this filesystem for a reference.

BR
Pavel

0 peng cheng over 10 years ago in reply to Pavel Botev

Prodigy 130 points

Hi Pavel, I have solved this problem.

There is something wrong configure in my kernel code /kernel/sound/soc/codec/wm8960.c file . I changed it , and now it workd fine.

I delete the two below code in function: "wm8960_hw_params(****)";

	snd_soc_write(codec,  0x0a, 0x1ff);
	snd_soc_write(codec,  0x0b, 0x1ff);

In my wm8960 datasheet, address 0xa 0xb control the left and right DAC volume. While some program access the alsa driver, the function will resetup the two reg status. So i delete this two code.

Thanks.

0 Pavel Botev over 10 years ago in reply to peng cheng

TI__Guru**** 170625 points

Hi Peng,

Thank you for sharing the solution.

Regards,
Pavel

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How to save volume set by amixer ?