Unverified Commit fe76d2e7 authored by Peter Ujfalusi's avatar Peter Ujfalusi Committed by Mark Brown
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ASoC: SOF: Intel: hda-pcm: Use dsp_max_burst_size_in_ms to place constraint 



If the PCM have the dsp_max_burst_size_in_ms set then place a constraint
to limit the minimum buffer time to avoid xruns caused by DMA bursts
spinning on the ALSA buffer.

Cc: stable@vger.kernel.org # 6.8
Signed-off-by: default avatarPeter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: default avatarKai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: default avatarPierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://msgid.link/r/20240321130814.4412-4-peter.ujfalusi@linux.intel.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 842bb8b6

sound/soc/sof/intel/hda-pcm.c

+21 −0
Original line number Diff line number Diff line
@@ -259,6 +259,27 @@ int hda_dsp_pcm_open(struct snd_sof_dev *sdev, 
		snd_pcm_hw_constraint_mask64(substream->runtime, SNDRV_PCM_HW_PARAM_FORMAT,

					     SNDRV_PCM_FMTBIT_S16 | SNDRV_PCM_FMTBIT_S32);



	/*

	 * The dsp_max_burst_size_in_ms is the length of the maximum burst size

	 * of the host DMA in the ALSA buffer.

	 *

	 * On playback start the DMA will transfer dsp_max_burst_size_in_ms

	 * amount of data in one initial burst to fill up the host DMA buffer.

	 * Consequent DMA burst sizes are shorter and their length can vary.

	 * To make sure that userspace allocate large enough ALSA buffer we need

	 * to place a constraint on the buffer time.

	 *

	 * On capture the DMA will transfer 1ms chunks.

	 *

	 * Exact dsp_max_burst_size_in_ms constraint is racy, so set the

	 * constraint to a minimum of 2x dsp_max_burst_size_in_ms.

	 */

	if (spcm->stream[direction].dsp_max_burst_size_in_ms)

		snd_pcm_hw_constraint_minmax(substream->runtime,

			SNDRV_PCM_HW_PARAM_BUFFER_TIME,

			spcm->stream[direction].dsp_max_burst_size_in_ms * USEC_PER_MSEC * 2,

			UINT_MAX);



	/* binding pcm substream to hda stream */

	substream->runtime->private_data = &dsp_stream->hstream;

	return 0;