>It would really help if you'd show us the code of the version of the
>driver that you're currently talking about.
Hi Clemens...
I had sent you the source file having pcm callbacks yesterday, now I
have modified the pointer function as follows, I am just giving the
pointer function here to avoid duplication, but please let me know in
case you want to have look at the entire file.
static snd_pcm_uframes_t snd_omap_alsa_pointer(snd_pcm_substream_t *substream)
{
struct omap_eac *chip = snd_pcm_substream_chip(substream);
snd_pcm_uframes_t pos = 0;
FN_ENTER;
pos = audio_get_dma_pos(&chip->s[substream->pstr->stream]);
printk("Returning pos = %d\n", pos);
return pos;
FN_EXIT;
}
static snd_pcm_uframes_t audio_get_dma_pos(struct audio_stream *s)
{
snd_pcm_substream_t *substream = s->stream;
snd_pcm_runtime_t *runtime = substream->runtime;
unsigned long flags;
dma_addr_t count;
unsigned long offset;
dma_addr_t src,dest;
if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
dest = omap_get_dma_dst_pos(s->lch[s->dma_q_head]);
offset = dest - runtime->dma_addr;
printk("dest is %u and offset is %u\n",dest,offset);
} else {
src = omap_get_dma_src_pos(s->lch[s->dma_q_head]);
offset = src - runtime->dma_addr;
printk("src is %u and offset is %u\n",dest,offset);
}
return bytes_to_frames(substream->runtime, offset);
}
And the log is as follows.
For the first time.
snd_omap_alsa_pointer start
src is 3246792928 and offset is 3304194048
Returning pos = 20742144
Inside snd_pcm_update_hw_ptr_pos, pos is 20742144
ALSA sound/core/pcm_lib.c:167: BUG: stream = 0, pos = 0x13c8000,
buffer size = 0x4000, period size = 0x800
returning pos 20742144
I can see things are horribaly wrong here....
On 6/26/07, Clemens Ladisch <cladisch@xxxxxxxxxxxx> wrote:
> Pharaoh . wrote:
> > After rewriting the pointer function
>
> It would really help if you'd show us the code of the version of the
> driver that you're currently talking about.
>
> > I am not getting the input/output error but I am getting underruns.
> > ...
> > ALSA sound/core/pcm_lib.c:167: BUG: stream = 0, pos = 0x1150000, buffer
> size = 0x4000, period size = 0x800
>
> Here, "pos" is the value returned by your pointer callback. This value
> should have been a frame number somewhere in the buffer, i.e., in the
> range 0..0x3fff. Apparently, the pointer callback doesn't correctly
> calculate this value.
>
> Please remove most printk()s, and add some in the pointer callback to
> show both the value that you get from the DMA controller, and the value
> that this function returns.
>
>
> Regards,
> Clemens
>
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