Re: [alsa-devel] [PATCH 1/2] ASoC: soc-cache: Use reg_def_copy instead of reg_cache_default

On Wed, 2011-01-05 at 15:04 -0600, Timur Tabi wrote:

Which is this line:

...

@@ -3463,6 +3464,19 @@ int snd_soc_register_codec(struct device *dev,

   /* allocate CODEC register cache */
   if (codec_drv->reg_cache_size && codec_drv->reg_word_size) {

•           reg_size = codec_drv->reg_cache_size * codec_drv->reg_word_size;
  

•           /* it is necessary to make a copy of the default register cache
  

•            * because in the case of using a compression type that requires
  

•            * the default register cache to be marked as __devinitconst the
  

•            * kernel might have freed the array by the time we initialize
  

•            * the cache.
  

•            */
  

•           codec->reg_def_copy = kmemdup(codec_drv->reg_cache_default,
  

•                                         reg_size, GFP_KERNEL);
  

The semantics behind this code is that if the driver provides a reg_cache_size and a reg_word_size it *should* provide a defaults register cache as well. If you want to manage your own register cache in the driver which is not advised, you will have to add similar functionality in your _priv struct. If you require more flexible functionality you need to consider implementing a sensible strategy and submitting it as a patch.

Thanks, Dimitris