On 02/05/2014 10:11 AM, Jean-Francois Moine wrote: > On Tue, 4 Feb 2014 18:06:25 +0000 > Mark Brown <broonie at 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. >
The startup function is the right place. But instead of modifying the DAI use snd_pcm_hw_constraint_mask64(), snd_pcm_hw_constraint_list(), etc. to setup the additional constraints that come from the EDID. Bonus points for making this a generic helper function that takes a runtime and a EDID and then applies the EDID constraints on the runtime. - Lars
