Re: [alsa-devel] [PATCH v3 4/5] ASoC: tda998x: adjust the audio hw parameters from EDID

On Tue, 4 Feb 2014 18:06:25 +0000 Mark Brown broonie@kernel.org wrote:

On Mon, Jan 27, 2014 at 09:48:54AM +0100, Jean-Francois Moine wrote:

...

• /* change the snd_soc_pcm_stream values of the driver */
  

• stream->rates = rate_mask;
  

• stream->channels_max = max_channels;
  

• stream->formats = formats;
  

...

• /* copy the DAI driver to a writable area */
• dai_drv = devm_kzalloc(&pdev->dev, sizeof(tda998x_dai), GFP_KERNEL);
• if (!dai_drv)

• return -ENOMEM;
  

• memcpy(dai_drv, tda998x_dai, sizeof(tda998x_dai));

The code should be doing this by setting constraints based on the current setup rather than by editing the data structure - the expecation is very much that the data won't change so this prevents surprises with future work on the core.

As it is done in the soc core, in soc_pcm_open(), the runtime hw_params are initialized after the call to the CODEC startup, and the next CODEC event is hw_params() when the user has already chosen all the parameters.

So, in the CODEC, I don't see how I could update the parameters dictated by the EDID otherwise in changing the DAI driver parameters.