Not writing the full buffer every 9th time

[ksmarty]

Hello! I'm encountering a weird issue where I'm able to write 8 full buffers of 4080 bytes, but then only 84/128 bytes of the buffer are written.
It follows this pattern:

4080 x 8
84
4080 x 8
128
4080 x 8
128
...

I confirmed the buffer has a full 4080 bytes each time, and it's evident that data is missing when listening to the audio.

This is the main loop where the issue is happening:

  let mut data = [0u8; 4092];
  let mut transfer = i2s_rx.read_dma_circular_async(rx_buffer_i2s).unwrap();

  loop {
      let i2s_bytes_read = transfer.pop(&mut data).await.unwrap();

      let x = f.write(&data[..i2s_bytes_read]).await.unwrap();
      f.flush().await.unwrap();
      println!("{:?}", x);

      if button.is_low() {
          // Debounce
          button.wait_for_high().await;
          break;
      }
  }

You can find the full source code here: https://github.com/ksmarty/diane/blob/main/src/bin/async_main.rs

Please let me know any ideas you might have on why this is happening. Thanks!

[MabezDev]

Could you try and make the repro smaller? Ideally without any other peripherals in play, just SPI for the card.

[ksmarty]

https://github.com/ksmarty/diane/blob/repro/src/bin/async_main.rs

I've removed as much extra code as I could. I left the i2s microphone setup as I wasn't sure what to replace it with as a source of input data to fill the buffer. I can provide a schematic if needed.