Re: Test record program triggers pcm problems on -stable (was: Re: kern/21438: Sox recording in 16 bits creates a panic: no feed)

3- ioctls does not seem to work properly.
 
At some point in the code, I call the ioctls:
 
>  if (ioctl(fd, SOUND_PCM_READ_CHANNELS, &params->r_channels))
>    err(1, "ioctl for read channels failed");
>  if (ioctl(fd, SOUND_PCM_WRITE_CHANNELS, &params->w_channels))
>    err(1, "ioctl for write channels failed");
>
>(for example). Now the value of params->*_channels is 2 in both cases.
>The output of the program, however, is:
>
>             read       write      units
>DSP device : /dev/dspW  /dev/dspW
>Rate       : 8000       44100      Hz
>Channels   : 1          2
>Size       : 16         16         bits
>
>ie, params->r_channels is *changed* from 2 to 1. Same goes for r_rate. I
>do not understand that behavior.
 
the SNDCTL_READ_*/SNDCTL_WRITE* ioctls do not do what you think they do.
 
the oss api does not support asymmetric settings for record and play.
SNDCTL_READ_* return the current settings; SNDCTL_WRITE* change the
settings.  these ioctls are deprecated.  the Right way to use the oss api is
documented in http://www.opensound.com/pguide/oss.pdf
 
    -cg
 
 
 
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