[alsa-devel] [PATCH 13/19] ASoC: Intel: mrfld: add bytes control for modules

[Lars-Peter Clausen]

On 06/23/2014 06:15 AM, Vinod Koul wrote:
> On Sat, Jun 21, 2014 at 08:19:13AM +0200, Lars-Peter Clausen wrote:
>>>>>>> +static const struct snd_kcontrol_new sst_algo_controls[] = {
>>>>>>> +	SST_ALGO_KCONTROL_BYTES("media_loop1_out", "fir", 272, SST_MODULE_ID_FIR_24,
>>>>>>> +		 SST_PATH_INDEX_MEDIA_LOOP1_OUT, 0, SST_TASK_SBA, SBA_VB_SET_FIR),
>>>>>>> +	SST_ALGO_KCONTROL_BYTES("media_loop1_out", "iir", 300, SST_MODULE_ID_IIR_24,
>>>>>>> +		SST_PATH_INDEX_MEDIA_LOOP1_OUT, 0, SST_TASK_SBA, SBA_VB_SET_IIR),
>>>>>>> +	SST_ALGO_KCONTROL_BYTES("media_loop1_out", "mdrp", 286, SST_MODULE_ID_MDRP,
>>>>>>> +		SST_PATH_INDEX_MEDIA_LOOP1_OUT, 0, SST_TASK_SBA, SBA_SET_MDRP),
>>>>>>> +	SST_ALGO_KCONTROL_BYTES("media_loop2_out", "fir", 272, SST_MODULE_ID_FIR_24,
>>>>>>> +		SST_PATH_INDEX_MEDIA_LOOP2_OUT, 0, SST_TASK_SBA, SBA_VB_SET_FIR),
>>>>>>> +	SST_ALGO_KCONTROL_BYTES("media_loop2_out", "iir", 300, SST_MODULE_ID_IIR_24,
>>>>>>> +		SST_PATH_INDEX_MEDIA_LOOP2_OUT, 0, SST_TASK_SBA, SBA_VB_SET_IIR),
>>>>>>> +	SST_ALGO_KCONTROL_BYTES("media_loop2_out", "mdrp", 286, SST_MODULE_ID_MDRP,
>>>>>>> +		SST_PATH_INDEX_MEDIA_LOOP2_OUT, 0, SST_TASK_SBA, SBA_SET_MDRP),
>>>>>>> +	SST_ALGO_KCONTROL_BYTES("sprot_loop_out", "lpro", 192, SST_MODULE_ID_SPROT,
>>>>>>> +		SST_PATH_INDEX_SPROT_LOOP_OUT, 0, SST_TASK_SBA, SBA_VB_LPRO),
>>>>>>> +	SST_ALGO_KCONTROL_BYTES("codec_in0", "dcr", 52, SST_MODULE_ID_FILT_DCR,
>>>>>>> +		SST_PATH_INDEX_CODEC_IN0, 0, SST_TASK_SBA, SBA_VB_SET_IIR),
>>>>>>> +	SST_ALGO_KCONTROL_BYTES("codec_in1", "dcr", 52, SST_MODULE_ID_FILT_DCR,
>>>>>>> +		SST_PATH_INDEX_CODEC_IN1, 0, SST_TASK_SBA, SBA_VB_SET_IIR),
>>>>>>
>>>>>>
>>>>>> You are creating a lot of global non-const variables here that are
>>>>>> later modified in the put and get handlers and also elsewhere.
>>>>> Sorry which ones above are modfied. Above values are information for headers of
>>>>> IPCs which we send to DSPs
>>>>>
>>>>
>>>> The SST_ALGO_CTL_VALUE() macro uses compound literals to create a
>>>> global (nameless) struct. A pointer to this struct is assigned to
>>>> the kcontrols private_value field. This is later read and the struct
>>>> is modified.
>>> Yes but not the above values as these as IPC header info which DSP needs.
>>>
>>
>> The SST_ALGO_KCONTROL_BYTES() macro calls SST_ALGO_KCONTROL() which
>> in return calls SST_ALGO_CTL_VALUE()
> Yes and
> #define SST_ALGO_CTL_VALUE(xcount, xtype, xpipe, xmod, xtask, xcmd)	\
>          (struct sst_algo_control){					\
>                  .max = xcount + sizeof(u16), .type = xtype, .module_id = xmod,\
>                  .pipe_id = xpipe, .task_id = xtask, .cmd_id = xcmd,\
>          }
>
> So these values passed above are filled here and put in private_data as you
> rightly noticed. But later on get/put handlers will not modify these specfic
> value but other private value. Above are used _only_ for IPC headers to DSP so
> we cant afford to modify them. We cna try making these values above as
> consts, static

Ok, but how does this work, where does the different private_value come from?

- Lars