[alsa-devel] [PATCH 01/21] ASoC: SOF: Intel: Add BYT, CHT and BSW DSP HW support.

[Pierre-Louis Bossart]

On 1/22/19 1:35 AM, Daniel Baluta wrote:
>> +static int byt_send_msg(struct snd_sof_dev *sdev, struct snd_sof_ipc_msg *msg)
>> +{
>> +       u64 cmd = msg->header;
>> +
>> +       /* send the message */
>> +       sof_mailbox_write(sdev, sdev->host_box.offset, msg->msg_data,
>> +                         msg->msg_size);
> I was wondering if the mailbox shared memory wouldn't be better
> implemented as a queue.
> Do you support playing multiple streams in parallel?
>
> We have this use case where we need to to memory to memory
> decoding/encoding with lots
> of streams in parallel.

Sorry Daniel, I didn't get your point.

we do support multiple streams in parallel and there's been quite a few 
issues fixed in the IPC mechanisms due to concurrency. The IPC mechanism 
is serialized however since there are only few resources available, 
typically only a couple of doorbell registers and a small memory window. 
For multiple streams the PCM data is exchanged over DMA typically - the 
streams don't go over the IPC channel but the information related to a 
stream is passed using a tag or ID.

Can you clarify what you had in mind?