`/ET!-i1S!-i wrote:

1. I guess pulse audio inturn calls Alsa and i want to write a Alsa driver.

But the sound cards on the networked PCs already have drivers.

The problem i am facing is receiving Alsa buffer to my buffer

Your driver's buffer _is_ the ALSA buffer.

and updating the buffer position to middle layer.

The hardware position is returned by the pointer callback. The software position should be of no concern to the driver.

2. Is it substream->runtime->dma_area or substream->dma_buffer.area holds

the audio data? What is the difference between them?

These fields are controlled by your driver, although typically they are set by ALSA helper functions.

substream->dma_buffer is the preallocated buffer; if your driver doesn't do preallocation, it is not set. The actual buffer, if it exists and is accessible by the CPU from kernel space, is in substream->runtime->dma_area.

Regards, Clemens