Hello,

I hope someone can help me understand the concept of ping-pong dma with ALSA. I am using davinci soc: /sound/soc/davinci/davinci_pcm.c But I am not sure if it using ping-pong dma or not. In the header of "davinci_pcm_enqueue_dma" function it states "Not used with ping/pong", but inside I see that it use period parameter in order to set the offset inside the dma buffer which is used. So, does it mean that ping-pong is used or not ?

/* * Not used with ping/pong */ static void davinci_pcm_enqueue_dma(struct snd_pcm_substream *substream) .....

period_size = snd_pcm_lib_period_bytes(substream); dma_offset = prtd->period * period_size; dma_pos = runtime->dma_addr + dma_offset; ....

acnt = prtd->params->acnt; edma_set_src(link, src, INCR, W8BIT); edma_set_dest(link, dst, INCR, W8BIT); ...... }

Regards, Ran