This is a note to let you know that I've just added the patch titled
ASoC: SOF: Intel: hda-pcm: Use dsp_max_burst_size_in_ms to place constraint
to the 6.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
asoc-sof-intel-hda-pcm-use-dsp_max_burst_size_in_ms-to-place-constraint.patch
and it can be found in the queue-6.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From fe76d2e75a6da97edd2b4ec5cfb9efd541be087a Mon Sep 17 00:00:00 2001
From: Peter Ujfalusi <peter.ujfalusi@xxxxxxxxxxxxxxx>
Date: Thu, 21 Mar 2024 15:08:00 +0200
Subject: ASoC: SOF: Intel: hda-pcm: Use dsp_max_burst_size_in_ms to place constraint
From: Peter Ujfalusi <peter.ujfalusi@xxxxxxxxxxxxxxx>
commit fe76d2e75a6da97edd2b4ec5cfb9efd541be087a upstream.
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@xxxxxxxxxxxxxxx # 6.8
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxxxxxxxxxxx>
Reviewed-by: Kai Vehmanen <kai.vehmanen@xxxxxxxxxxxxxxx>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
Link: https://msgid.link/r/20240321130814.4412-4-peter.ujfalusi@xxxxxxxxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
sound/soc/sof/intel/hda-pcm.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/sound/soc/sof/intel/hda-pcm.c b/sound/soc/sof/intel/hda-pcm.c
index 18f07364d219..69fefcd1abc5 100644
--- a/sound/soc/sof/intel/hda-pcm.c
+++ b/sound/soc/sof/intel/hda-pcm.c
@@ -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;
--
2.44.0
Patches currently in stable-queue which might be from peter.ujfalusi@xxxxxxxxxxxxxxx are
queue-6.8/asoc-sof-intel-hda-implement-get_stream_position-linear-link-position.patch
queue-6.8/asoc-sof-intel-mtl-lnl-use-the-generic-get_stream_position-callback.patch
queue-6.8/asoc-sof-add-dsp_max_burst_size_in_ms-member-to-snd_sof_pcm_stream.patch
queue-6.8/asoc-sof-intel-hda-pcm-use-dsp_max_burst_size_in_ms-to-place-constraint.patch
queue-6.8/asoc-sof-intel-hda-common-ops-do-not-set-the-get_stream_position-callback.patch
queue-6.8/asoc-sof-intel-set-the-dai-host-get-frame-byte-counter-callbacks.patch
queue-6.8/asoc-sof-introduce-a-new-callback-pair-to-be-used-for-pcm-delay-reporting.patch
queue-6.8/asoc-sof-ipc4-pcm-use-the-snd_sof_pcm_get_dai_frame_counter-for-pcm_delay.patch
queue-6.8/asoc-sof-ipc4-topology-save-the-dma-maximum-burst-size-for-pcms.patch
queue-6.8/alsa-hda-add-pplcllpl-u-members-to-hdac_ext_stream.patch
queue-6.8/asoc-sof-remove-the-get_stream_position-callback.patch
queue-6.8/asoc-sof-ipc4-pcm-correct-the-delay-calculation.patch
queue-6.8/asoc-sof-ipc4-pcm-combine-the-sof_ipc4_pipe_paused-cases-in-pcm_trigger.patch
queue-6.8/asoc-sof-sof-pcm-add-pointer-callback-to-sof_ipc_pcm_ops.patch
queue-6.8/asoc-sof-intel-hda-compensate-llp-in-case-it-is-not-reset.patch
queue-6.8/asoc-sof-ipc4-pcm-move-struct-sof_ipc4_timestamp_info-definition-locally.patch
queue-6.8/asoc-sof-ipc4-pcm-invalidate-the-stream_start_offset-in-paused-state.patch
