Pharaoh . wrote:
I am reading 'Wring an alsa driver'. It says following about the private_data:
You can allocate a record for the substream and store it in runtime->private_data. Usually, this is done in the open callback. Don't mix this with pcm->private_data. The pcm->private_data usually points the chip instance assigned statically at the creation of PCM, while the runtime->private_data points a dynamic data created at the PCM open callback.
What does static and dynamic mean here?
Nothing much. "Static" just means that this is not allocated/freed together with a stream's runtime. The my_chip data is usually allocated from the heap, but the runtime->private_data is _more_ dynamic because it is allocated every time a stream is opened.
HTH Clemens