ASoC: SOF: Intel: hda: Disable DMI L1 entry during capture

There is a known issue on some Intel platforms which causes
pause/release to run into xrun's during capture usecases.
The suggested workaround to address the issue is to
disable the entry of lower power L1 state in the physical
DMI link when there is a capture stream open.

Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20190927200538.660-14-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 38 insertions, 7 deletions

diff --git a/sound/soc/sof/intel/hda-stream.c b/sound/soc/sof/intel/hda-stream.c
index ad8d41f22e92..2c7447188402 100644
--- a/sound/soc/sof/intel/hda-stream.c
+++ b/sound/soc/sof/intel/hda-stream.c
@@ -185,6 +185,17 @@ hda_dsp_stream_get(struct snd_sof_dev *sdev, int direction)
 			direction == SNDRV_PCM_STREAM_PLAYBACK ?
 			"playback" : "capture");
 
+	/*
+	 * Disable DMI Link L1 entry when capture stream is opened.
+	 * Workaround to address a known issue with host DMA that results
+	 * in xruns during pause/release in capture scenarios.
+	 */
+	if (!IS_ENABLED(SND_SOC_SOF_HDA_ALWAYS_ENABLE_DMI_L1))
+		if (stream && direction == SNDRV_PCM_STREAM_CAPTURE)
+			snd_sof_dsp_update_bits(sdev, HDA_DSP_HDA_BAR,
+						HDA_VS_INTEL_EM2,
+						HDA_VS_INTEL_EM2_L1SEN, 0);
+
 	return stream;
 }
 
@@ -193,23 +204,43 @@ int hda_dsp_stream_put(struct snd_sof_dev *sdev, int direction, int stream_tag)
 {
 	struct hdac_bus *bus = sof_to_bus(sdev);
 	struct hdac_stream *s;
+	bool active_capture_stream = false;
+	bool found = false;
 
 	spin_lock_irq(&bus->reg_lock);
 
-	/* find used stream */
+	/*
+	 * close stream matching the stream tag
+	 * and check if there are any open capture streams.
+	 */
 	list_for_each_entry(s, &bus->stream_list, list) {
-		if (s->direction == direction &&
-		    s->opened && s->stream_tag == stream_tag) {
+		if (!s->opened)
+			continue;
+
+		if (s->direction == direction && s->stream_tag == stream_tag) {
 			s->opened = false;
-			spin_unlock_irq(&bus->reg_lock);
-			return 0;
+			found = true;
+		} else if (s->direction == SNDRV_PCM_STREAM_CAPTURE) {
+			active_capture_stream = true;
 		}
 	}
 
 	spin_unlock_irq(&bus->reg_lock);
 
-	dev_dbg(sdev->dev, "stream_tag %d not opened!\n", stream_tag);
-	return -ENODEV;
+	/* Enable DMI L1 entry if there are no capture streams open */
+	if (!IS_ENABLED(SND_SOC_SOF_HDA_ALWAYS_ENABLE_DMI_L1))
+		if (!active_capture_stream)
+			snd_sof_dsp_update_bits(sdev, HDA_DSP_HDA_BAR,
+						HDA_VS_INTEL_EM2,
+						HDA_VS_INTEL_EM2_L1SEN,
+						HDA_VS_INTEL_EM2_L1SEN);
+
+	if (!found) {
+		dev_dbg(sdev->dev, "stream_tag %d not opened!\n", stream_tag);
+		return -ENODEV;
+	}
+
+	return 0;
 }
 
 int hda_dsp_stream_trigger(struct snd_sof_dev *sdev,