Re: [alsa-devel] [PATCH] ASoC: atmel_ssc_dai: Track playback and capture CMR dividers separately.

[Bo Shen]

Hi Peter,

On 10/22/2014 12:47 PM, Peter Rosin wrote:
> Hi!
>
> > Hi Peter,
> >
> > On 10/21/2014 09:05 PM, Peter Rosin wrote:
> > > I did some further tests, and the following program fails without the patch:
> >
> > With the patch, it is OK?
>
> Yes.
>
> > > #include <sys/ioctl.h>
> > > #include <unistd.h>
> > > #include <fcntl.h>
> > > #include <sys/soundcard.h>
> > >
> > > int
> > > main(void)
> > > {
> > > 	int fd;
> > > 	int format;
> > > 	int channels;
> > >
> > > 	if ((fd = open("/dev/dsp", O_WRONLY, 0)) == -1) {
> > > 		perror("open");
> > > 		return 1;
> > > 	}
> > > 	format = AFMT_S16_LE;
> > > 	if (ioctl(fd, SNDCTL_DSP_SETFMT, &format) == -1) {
> > > 		perror("SNDCTL_DSP_SETFMT");
> > > 		return 1;
> > > 	}
> > > 	channels = 2;
> > > 	if (ioctl(fd, SNDCTL_DSP_CHANNELS, &channels) == -1) {
> > > 		perror("SNDCTL_DSP_CHANNELS");
> > > 		return 1;
> > > 	}
> > > 	return 0;
> > > }
> > >
> > > Output:
> > > SNDCTL_DSP_CHANNELS: Device or resource busy
> >
> > This return from codec or from atmel_ssc_dai?
>
> This -EBUSY definitely comes from atmel_ssc_set_dai_sysclk, when my
> card-driver tries to set ATMEL_SSC_CMR_DIV. With the patch, it works.
> (the codec is spdif-transmitter, since the i2c interface of the actual tfa9879
> codec is not directly reachable from the linux cpu, but that has nothing to
> do with this issue).

I try to reproduce it (using the code your pasted directly) on atmel 
sama5d3xek with wm8904 code, don't meet this error.

I also go through the OSS code, I still don't find this is related with 
atmel_ssc_set_dai_sysclk.

So, am I missing something or something else?

> > > (I admin to having edited the above code slightly in this mail, so I
> s/admin/admit/
> > > might have introduced some silly bug, but you get what I mean, just
> > > open the device and request some parameters, and boom: -EBUSY)
>
> Cheers,
> Peter

Best Regards,
Bo Shen
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