Re: [PATCH 8/8] ASoC: SOF: Intel: add .ack support for HDaudio platforms

On Thu, 10 Jun 2021 22:53:26 +0200, Pierre-Louis Bossart wrote:

+/* update SPIB register with appl position */ +int hda_dsp_pcm_ack(struct snd_sof_dev *sdev, struct snd_pcm_substream *substream) +{

• struct hdac_stream *hstream = substream->runtime->private_data;
• struct hdac_ext_stream *stream = stream_to_hdac_ext_stream(hstream);
• struct snd_pcm_runtime *runtime = substream->runtime;
• ssize_t appl_pos, buf_size;
• u32 spib;
• if (!hda_disable_rewinds)

• return 0;
  

• /*

• * paranoia check: if a rewind request took place after the RUN bits were programmed,
  

• * deny it since hardware only supports monotonic (modulo) increments for SPIB.
  

• */
  

• if (hstream->running) {

• if (runtime->control->appl_ptr < stream->old_appl_ptr)
  

• 	return -EINVAL;
  

This condition won't be enough when the appl_ptr overlap the buffer boundary. It's still possible on 32bit architecture.

thanks,

Takashi