[TW#19859] Zero i2s dma buffer after write, so we have silence after buffer underflow

[ghost]

See also: earlephilhower/ESP8266Audio#48

If a ets_memset(finish_desc->buf, 0, finish_desc->buf_size);
is added before

esp-idf/components/driver/i2s.c

Line 504 in da27816

xQueueSendFromISR(p_i2s->tx->queue, (void*)(&finish_desc->buf), &high_priority_task_awoken);

It would give us silence when a i2s buffer underflow happens, instead of the looping noise we get now :)

[jeanthom]

I guess that some code has been changed in esp-idf (ets_memset() doesn't exist anymore, finish_desc's buf_size element has been renamed to size), therefore the correct fix would be this :

memset(finish_desc->buf, 0, finish_desc->size);

[h3ndrik]

this doesn't result in a compiler-warning:
memset((void*)(finish_desc->buf), 0, finish_desc->size);

but is that correct? does it zero all the dma buffers? i still have problems with earlephilhower/ESP8266Audio#48 even with this patch.
but that is probably another bug on my side.