[alsa-devel] Please help in adding ams-delta support to ASoC

[Janusz Krzysztofik]

Wednesday 10 June 2009 12:53:42 Peter Ujfalusi napisał(a):
> On Wednesday 10 June 2009 13:27:38 ext Janusz Krzysztofik wrote:
> Just out of curiosity, can you try this one as well:
>
> --- a/sound/soc/omap/omap-mcbsp.c
> +++ b/sound/soc/omap/omap-mcbsp.c
> @@ -191,6 +191,7 @@ static int omap_mcbsp_dai_trigger(struct
> snd_pcm_substream *substream, int cmd,
>         case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
>                 if (!mcbsp_data->active++)
>                         omap_mcbsp_start(mcbsp_data->bus_id);
> +               omap_mcbsp_pollwrite(mcbsp_data->bus_id, 0xdb55);
>                 break;
>
> basically write 0xdb55 to the DXR1 register (0xdb55 is 1101101101010101)
> With this, if McBSP is operating correctly you should be seeing this
> pattern going to the codec.

Peter,

I am not sure how did you expect me to see this pattern. On a scope screen? 
Unforunatelly I had to return the scope this morning.

I have further modified the code like this:

@@ -25,6 +25,7 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/device.h>
+#include <linux/random.h>
 #include <sound/core.h>
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
@@ -186,7 +186,7 @@ static int omap_mcbsp_dai_trigger(struct snd_pcm_substream 
*substream, int cmd,
        struct snd_soc_pcm_runtime *rtd = substream->private_data;
        struct snd_soc_dai *cpu_dai = rtd->dai->cpu_dai;
        struct omap_mcbsp_data *mcbsp_data = to_mcbsp(cpu_dai->private_data);
-       int err = 0;
+       int i, err = 0;

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
@@ -191,6 +191,8 @@ static int omap_mcbsp_dai_trigger(struct snd_pcm_substream 
*substream, int cmd,
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
                if (!mcbsp_data->active++)
                        omap_mcbsp_start(mcbsp_data->bus_id);
+               for (i = 8000; i > 0; i--)
+                       omap_mcbsp_pollwrite(mcbsp_data->bus_id, (u16)random32
());
                break;

        case SNDRV_PCM_TRIGGER_STOP:

in hope I should be able to hear a noise for one second, shouldn't I.

> If it does, than we have some problems with the 
> McBSP/DMA cooperation, if this pattern is not seen on the bus, than the
> McBSP is not shifting data out for some reason.

Now aplay returns 1 second later than before, so I conclude the loop is 
processed correctly. However, I am not able to hear a single ripple nor see 
any error messages from omap_mcbsp_pollwrite() :(, so it looks like the 
latter is more probable.

Janusz
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