ASoC: SOF: Intel: hda: Do not re-enable L1 if disabled before suspend

We have a workaround in place to address a known issue with host DMA
running into xruns when capture streams are running. But when resuming
from Sx, we unconditionally re-enable DMI L1 without taking the
workaround into account and this could lead to xruns when a suspended
capture stream is restarted.

To fix this rename the flag l1_support_enabled to l1_disabled in struct
sof_intel_hda_dev to save the L1 disabled status which can be
set/cleared when we get/put a stream and use the flag to determine if DMI
L1 should enabled or not during the post_fw_run op.
Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Link: https://lore.kernel.org/r/20230220075804.4829-2-peter.ujfalusi@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

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

@@ -158,16 +158,18 @@ void hda_dsp_ctrl_misc_clock_gating(struct snd_sof_dev *sdev, bool enable)
  */
 int hda_dsp_ctrl_clock_power_gating(struct snd_sof_dev *sdev, bool enable)
 {
+	struct sof_intel_hda_dev *hda = sdev->pdata->hw_pdata;
 	u32 val;
 
 	/* enable/disable audio dsp clock gating */
 	val = enable ? PCI_CGCTL_ADSPDCGE : 0;
 	snd_sof_pci_update_bits(sdev, PCI_CGCTL, PCI_CGCTL_ADSPDCGE, val);
 
-	/* enable/disable DMI Link L1 support */
+	/* disable the DMI link when requested. But enable only if it wasn't disabled previously */
 	val = enable ? HDA_VS_INTEL_EM2_L1SEN : 0;
-	snd_sof_dsp_update_bits(sdev, HDA_DSP_HDA_BAR, HDA_VS_INTEL_EM2,
-				HDA_VS_INTEL_EM2_L1SEN, val);
+	if (!enable || !hda->l1_disabled)
+		snd_sof_dsp_update_bits(sdev, HDA_DSP_HDA_BAR, HDA_VS_INTEL_EM2,
+					HDA_VS_INTEL_EM2_L1SEN, val);
 
 	/* enable/disable audio dsp power gating */
 	val = enable ? 0 : PCI_PGCTL_ADSPPGD;

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

@@ -776,7 +776,7 @@ int hda_dsp_resume(struct snd_sof_dev *sdev)
 		}
 
 		/* restore L1SEN bit */
-		if (hda->l1_support_changed)
+		if (hda->l1_disabled)
 			snd_sof_dsp_update_bits(sdev, HDA_DSP_HDA_BAR,
 						HDA_VS_INTEL_EM2,
 						HDA_VS_INTEL_EM2_L1SEN, 0);
@@ -868,11 +868,9 @@ int hda_dsp_suspend(struct snd_sof_dev *sdev, u32 target_state)
 		}
 
 		/* enable L1SEN to make sure the system can enter S0Ix */
-		hda->l1_support_changed =
-			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 (hda->l1_disabled)
+			snd_sof_dsp_update_bits(sdev, HDA_DSP_HDA_BAR, HDA_VS_INTEL_EM2,
+						HDA_VS_INTEL_EM2_L1SEN, HDA_VS_INTEL_EM2_L1SEN);
 
 		/* stop the CORB/RIRB DMA if it is On */
 		hda_codec_suspend_cmd_io(sdev);

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

@@ -182,6 +182,7 @@ int hda_dsp_stream_spib_config(struct snd_sof_dev *sdev,
 struct hdac_ext_stream *
 hda_dsp_stream_get(struct snd_sof_dev *sdev, int direction, u32 flags)
 {
+	struct sof_intel_hda_dev *hda = sdev->pdata->hw_pdata;
 	struct hdac_bus *bus = sof_to_bus(sdev);
 	struct sof_intel_hda_stream *hda_stream;
 	struct hdac_ext_stream *hext_stream = NULL;
@@ -222,10 +223,12 @@ hda_dsp_stream_get(struct snd_sof_dev *sdev, int direction, u32 flags)
 	 * Workaround to address a known issue with host DMA that results
 	 * in xruns during pause/release in capture scenarios.
 	 */
-	if (!(flags & SOF_HDA_STREAM_DMI_L1_COMPATIBLE))
+	if (!(flags & SOF_HDA_STREAM_DMI_L1_COMPATIBLE)) {
 		snd_sof_dsp_update_bits(sdev, HDA_DSP_HDA_BAR,
 					HDA_VS_INTEL_EM2,
 					HDA_VS_INTEL_EM2_L1SEN, 0);
+		hda->l1_disabled = true;
+	}
 
 	return hext_stream;
 }
@@ -233,6 +236,7 @@ hda_dsp_stream_get(struct snd_sof_dev *sdev, int direction, u32 flags)
 /* free a stream */
 int hda_dsp_stream_put(struct snd_sof_dev *sdev, int direction, int stream_tag)
 {
+	struct sof_intel_hda_dev *hda = sdev->pdata->hw_pdata;
 	struct hdac_bus *bus = sof_to_bus(sdev);
 	struct sof_intel_hda_stream *hda_stream;
 	struct hdac_ext_stream *hext_stream;
@@ -264,9 +268,11 @@ int hda_dsp_stream_put(struct snd_sof_dev *sdev, int direction, int stream_tag)
 	spin_unlock_irq(&bus->reg_lock);
 
 	/* Enable DMI L1 if permitted */
-	if (dmi_l1_enable)
+	if (dmi_l1_enable) {
 		snd_sof_dsp_update_bits(sdev, HDA_DSP_HDA_BAR, HDA_VS_INTEL_EM2,
 					HDA_VS_INTEL_EM2_L1SEN, HDA_VS_INTEL_EM2_L1SEN);
+		hda->l1_disabled = false;
+	}
 
 	if (!found) {
 		dev_err(sdev->dev, "%s: stream_tag %d not opened!\n",

sound/soc/sof/intel/hda.h

@@ -502,7 +502,7 @@ struct sof_intel_hda_dev {
 	u32 stream_max;
 
 	/* PM related */
-	bool l1_support_changed;/* during suspend, is L1SEN changed or not */
+	bool l1_disabled;/* is DMI link L1 disabled? */
 
 	/* DMIC device */
 	struct platform_device *dmic_dev;