[alsa-devel] soft vol

[Takashi Iwai]

At Fri, 11 May 2007 12:36:01 +0200,
Michel Benoit wrote:
> 
> Hello
> 
> Now that I have my pcm playback working with aplay with our at91 aSoc
> sound driver I would like to control the volume with softvol.
> 
> I followed the instructions from
> http://alsa.opensrc.org/How_to_use_softvol_to_control_the_master_volume
> and I have the following asound.con file in /etc
> 
> pcm.!default {
>     type             plug
>     slave.pcm       "softvol"
> }
> 
> pcm.softvol {
>     type        softvol
>     slave {
>         pcm     "plughw:0,0"
>     }
>     control {
>         name    "PCM volume"
>         card    0
>     }
> }
> 
> When I play a wav file directly to the device it works fine:
> 
> # aplay -Dplughw:0,0 Front_Center.wav
> Playing WAVE 'Front_Center.wav' : Signed 16 bit Little Endian, Rate
> 48000 Hz, Mono
> 
> but when I try to use the default softvol device I get the following
> output (and no sound):
> 
> # aplay Front_Center.wav
> Playing WAVE 'Front_Center.wav' : Signed 16 bit Little Endian, Rate
> 48000 Hz, Mono
> ALSA sound/core/control.c:1244: unknown ioctl = 0xc2c45512
> ALSA sound/core/control.c:1244: unknown ioctl = 0xc2c45512
> ALSA sound/core/control.c:1244: unknown ioctl = 0xc2c45512
> ALSA sound/core/control.c:1244: unknown ioctl = 0xc2c45512
> ALSA sound/core/control.c:1244: unknown ioctl = 0xc2c45512
> ...
> 
> Does anyone have any ideas as to why this is happening?

This should be SNDRV_CTL_IOCTL_ELEM_READ.

Could you check which number this ioctl is in the kernel code?
e.g. try printk("0x%x\n", SNDRV_CTL_IOCTL_ELEM_READ) in kernel
and in alsa-lib, too.


Takashi