Re: [PATCH 1/4] ASoC: qcom: audioreach: compute active channel maps from channel_map

[Srinivas Kandagatla <srinivas.kandagatla@oss.qualcomm.com>]

On 6/16/26 4:12 PM, Neil Armstrong wrote:
> On 6/16/26 16:59, Srinivas Kandagatla wrote:
>>
>>
>> On 6/15/26 2:54 PM, Neil Armstrong wrote:
>>> On 6/15/26 11:36, Srinivas Kandagatla wrote:
>>>> On 6/15/26 10:31 AM, Neil Armstrong wrote:
>>>>> On 6/15/26 10:38, Srinivas Kandagatla wrote:
>>>>>>
>>>>>>
>>>>>> On 6/10/26 8:41 AM, Neil Armstrong wrote:
>>>>>>> The Qualcom SM8650 based Ayaneo Pocket S2 gaming device has a set
>>>>>>> of 2 WSA speakers connected on the WSA2 lines.
>>>>>>>
>>>>>>> But the Audioreach DSP only handles WSA2 in pair with the WSA
>>>>>>> interface by using the upper bits of the active_channels_mask
>>>>>>> for WSA2 and the lower bits for WSA:
>>>>>>>
>>>>>>> /-------------------------------------------------\
>>>>>>> | Bits  |     3    |     2    |   1     |     0   |
>>>>>>> |-------------------------------------------------|
>>>>>>> | Line  | WSA2 Ch2 | WSA2 Ch1 | WSA Ch2 | WSA Ch1 |
>>>>>>> \-------------------------------------------------/
>>>>>>>
>>>>>> No, this is not totally correct, if the setup only has WSA2, then
>>>>>> channel 0 and 1 should be WSA2 channels.
>>>>>>
>>>>>> What is the backend dai id that is in DT, it should be
>>>>>>
>>>>>>       sound-dai = <&q6apmbedai WSA2_CODEC_DMA_RX_0>;
>>>>>>
> 
> Yeah 0xC0 for active_channels_mask and channel_mapping =
> { PCM_CHANNEL_FL, PCM_CHANNEL_FR };
> 
> I tried to keep the leading 0, but since the channel_mapping table is
> allocated with
> the size of the num_channels parameter, you can ony have 2 entries.
> 
>>
>>  From DSP docs:
>> https://github.com/AudioReach/audioreach-engine/blob/master/fwk/api/
>> modules/media_fmt_api_basic.h#L780
>>
>> Channel[i] mapping describes channel i. Each element i of the array
>> describes channel i inside the buffer where i is less than num_channels.
>> An unused channel is set to 0.
>>
>>
>> So unused channels should be set to zero, but the patch padding the
>> channels starting form zero.
> 
> My understanding in my trial and error is that the DSP will map each
> entry of the channel_mapping to the active_channels_mask bits in order
> so you can have a non linear active_channels_mask like b10101010 which
> has 4 channels active and pass a channel_mapping table with 4 entries.
> 

You are correct, I was mis-interpreting some of the comments from
modules/media_fmt_api_basic.h specially the channel map comment.

Also confirmed this internally so we are good,

I tested this on T14s,

Tested-by: Srinivas Kandagatla <srinivas.kandagatla@oss.qualcomm.com>
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@oss.qualcomm.com>


--srini


> The is what I implemented here, and it gives a lot of flexibility on how
> to connect speakers to the interface.
> 
> Neil