[PATCH v2 0/4] ASoC: SOF: Intel: DMI L1 power optimization for HDaudio platforms

[PATCH v2 0/4] ASoC: SOF: Intel: DMI L1 power optimization for HDaudio platforms

[Pierre-Louis Bossart]

This patchset provides an optimization that result in significant power
savings on Intel HDAudio platforms using SOF (Sound Open Firmware).

We previously prevented the Intel DSP from enabling the DMI_L1
capability to work-around issues with pause on capture streams. It
turns out that this also prevented the platform from entering high C
states in full-duplex usages such as videoconferencing - a rather
basic use case since the start of the pandemic.

The support for pause_push/release was already a bit controversial for
Intel platforms, in theory platforms should only enable PAUSE if they
can resume on the same sample, which is not the case on any Intel
platform.

With this patchset, when the user enables DMI L1 via a kernel
parameter, the PAUSE support is disabled for capture streams. A kernel
parameter is far from ideal but it's a placeholder until we have an
API to negotiate capabilities between applications and driver, and
it's far less confusing than a Kconfig option.

Changes since v1:
Removal of SPIB support since it may conflict with Takashi's memalloc
changes. These SPIB changes will be provided after rebase.
Addition of one cleanup for cppcheck warning
Move all changes to intel/ directory, no changes in shared code
Flipped the logic: the selection of DMI L1 disables PAUSE

Pierre-Louis Bossart (4):
  ASoC: SOF: Intel: Kconfig: clarify DMI L1 option description
  ASoC: SOF: Intel: hda-stream: remove always true condition
  ASoC: SOF: Intel: simplify logic for DMI_L1 handling
  ASoC: SOF: Intel: make DMI L1 selection more robust

 sound/soc/sof/intel/Kconfig      | 10 ----------
 sound/soc/sof/intel/hda-pcm.c    | 16 ++++++++++++++--
 sound/soc/sof/intel/hda-stream.c | 11 +++++------
 3 files changed, 19 insertions(+), 18 deletions(-)

-- 
2.25.1

[PATCH v2 1/4] ASoC: SOF: Intel: Kconfig: clarify DMI L1 option description

[Pierre-Louis Bossart]

This option is only valid for HDaudio platforms. This was described in
the help but not explicit in the option description.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
---
 sound/soc/sof/intel/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/sof/intel/Kconfig b/sound/soc/sof/intel/Kconfig
index 4447f515e8b1..ef8cf95b0edc 100644
--- a/sound/soc/sof/intel/Kconfig
+++ b/sound/soc/sof/intel/Kconfig
@@ -250,7 +250,7 @@ config SND_SOC_SOF_HDA_PROBES
 	  If unsure, select "N".
 
 config SND_SOC_SOF_HDA_ALWAYS_ENABLE_DMI_L1
-	bool "SOF enable DMI Link L1"
+	bool "SOF Intel-HDA enable DMI Link L1"
 	help
 	  This option enables DMI L1 for both playback and capture
 	  and disables known workarounds for specific HDAudio platforms.
-- 
2.25.1

[PATCH v2 2/4] ASoC: SOF: Intel: hda-stream: remove always true condition

[Pierre-Louis Bossart]

We test if (!stream) and return and later on re-test for stream.
The second test is always true.

This was detected by cppcheck but only after additional code changes.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
---
 sound/soc/sof/intel/hda-stream.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/sof/intel/hda-stream.c b/sound/soc/sof/intel/hda-stream.c
index 40a3993ae2cb..5302464754f9 100644
--- a/sound/soc/sof/intel/hda-stream.c
+++ b/sound/soc/sof/intel/hda-stream.c
@@ -198,7 +198,7 @@ hda_dsp_stream_get(struct snd_sof_dev *sdev, int direction, u32 flags)
 	 * in xruns during pause/release in capture scenarios.
 	 */
 	if (!IS_ENABLED(CONFIG_SND_SOC_SOF_HDA_ALWAYS_ENABLE_DMI_L1))
-		if (stream && !(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);
-- 
2.25.1

[PATCH v2 3/4] ASoC: SOF: Intel: simplify logic for DMI_L1 handling

[Pierre-Louis Bossart]

We don't need to test in multiple places if the kconfig
SND_SOC_SOF_HDA_ALWAYS_ENABLE_DMI_L1 is enabled or not, we might as
well set the existing DMI_L1_COMPATIBLE flag.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
---
 sound/soc/sof/intel/hda-pcm.c    |  3 ++-
 sound/soc/sof/intel/hda-stream.c | 11 +++++------
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/sound/soc/sof/intel/hda-pcm.c b/sound/soc/sof/intel/hda-pcm.c
index df00db8369c7..59220fa1def1 100644
--- a/sound/soc/sof/intel/hda-pcm.c
+++ b/sound/soc/sof/intel/hda-pcm.c
@@ -229,7 +229,8 @@ int hda_dsp_pcm_open(struct snd_sof_dev *sdev,
 	}
 
 	/* All playback and D0i3 compatible streams are DMI L1 capable */
-	if (direction == SNDRV_PCM_STREAM_PLAYBACK ||
+	if (IS_ENABLED(CONFIG_SND_SOC_SOF_HDA_ALWAYS_ENABLE_DMI_L1) ||
+	    direction == SNDRV_PCM_STREAM_PLAYBACK ||
 	    spcm->stream[substream->stream].d0i3_compatible)
 		flags |= SOF_HDA_STREAM_DMI_L1_COMPATIBLE;
 
diff --git a/sound/soc/sof/intel/hda-stream.c b/sound/soc/sof/intel/hda-stream.c
index 5302464754f9..63c367478f1c 100644
--- a/sound/soc/sof/intel/hda-stream.c
+++ b/sound/soc/sof/intel/hda-stream.c
@@ -197,11 +197,10 @@ 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 (!IS_ENABLED(CONFIG_SND_SOC_SOF_HDA_ALWAYS_ENABLE_DMI_L1))
-		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);
+	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);
 
 	return stream;
 }
@@ -240,7 +239,7 @@ 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 (!IS_ENABLED(CONFIG_SND_SOC_SOF_HDA_ALWAYS_ENABLE_DMI_L1) && 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);
 
-- 
2.25.1

[PATCH v2 4/4] ASoC: SOF: Intel: make DMI L1 selection more robust

[Pierre-Louis Bossart]

Exposing the DMI L1 configuration as a kernel Kconfig option was in
hindsight a really bad idea. It led to several errors reported by
distributions which selected it by mistake.

The Kconfig is now replaced with a kernel parameter. Since DMI L1
entry is incompatible with pause on a capture stream, the latter is
disabled when the kernel parameter is set.

Experimental results show an increased residency in higher C states
and a significant decrease of system power consumption for "work from
home" usages such as VoIP calls.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
---
 sound/soc/sof/intel/Kconfig   | 10 ----------
 sound/soc/sof/intel/hda-pcm.c | 17 ++++++++++++++---
 2 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/sound/soc/sof/intel/Kconfig b/sound/soc/sof/intel/Kconfig
index ef8cf95b0edc..88b6176af021 100644
--- a/sound/soc/sof/intel/Kconfig
+++ b/sound/soc/sof/intel/Kconfig
@@ -249,16 +249,6 @@ config SND_SOC_SOF_HDA_PROBES
 	  Say Y if you want to enable probes.
 	  If unsure, select "N".
 
-config SND_SOC_SOF_HDA_ALWAYS_ENABLE_DMI_L1
-	bool "SOF Intel-HDA enable DMI Link L1"
-	help
-	  This option enables DMI L1 for both playback and capture
-	  and disables known workarounds for specific HDAudio platforms.
-	  Only use to look into power optimizations on platforms not
-	  affected by DMI L1 issues. This option is not recommended.
-	  Say Y if you want to enable DMI Link L1.
-	  If unsure, select "N".
-
 endif ## SND_SOC_SOF_HDA_COMMON
 
 config SND_SOC_SOF_HDA_LINK_BASELINE
diff --git a/sound/soc/sof/intel/hda-pcm.c b/sound/soc/sof/intel/hda-pcm.c
index 59220fa1def1..cc8ddef37f37 100644
--- a/sound/soc/sof/intel/hda-pcm.c
+++ b/sound/soc/sof/intel/hda-pcm.c
@@ -15,6 +15,7 @@
  * Hardware interface for generic Intel audio DSP HDA IP
  */
 
+#include <linux/moduleparam.h>
 #include <sound/hda_register.h>
 #include <sound/pcm_params.h>
 #include "../sof-audio.h"
@@ -27,6 +28,10 @@
 #define SDnFMT_BITS(x)	((x) << 4)
 #define SDnFMT_CHAN(x)	((x) << 0)
 
+static bool hda_always_enable_dmi_l1;
+module_param_named(always_enable_dmi_l1, hda_always_enable_dmi_l1, bool, 0444);
+MODULE_PARM_DESC(always_enable_dmi_l1, "SOF HDA always enable DMI l1");
+
 u32 hda_dsp_get_mult_div(struct snd_sof_dev *sdev, int rate)
 {
 	switch (rate) {
@@ -216,6 +221,7 @@ int hda_dsp_pcm_open(struct snd_sof_dev *sdev,
 		     struct snd_pcm_substream *substream)
 {
 	struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
+	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct snd_soc_component *scomp = sdev->component;
 	struct hdac_ext_stream *dsp_stream;
 	struct snd_sof_pcm *spcm;
@@ -228,9 +234,14 @@ int hda_dsp_pcm_open(struct snd_sof_dev *sdev,
 		return -EINVAL;
 	}
 
-	/* All playback and D0i3 compatible streams are DMI L1 capable */
-	if (IS_ENABLED(CONFIG_SND_SOC_SOF_HDA_ALWAYS_ENABLE_DMI_L1) ||
-	    direction == SNDRV_PCM_STREAM_PLAYBACK ||
+	/*
+	 * All playback streams are DMI L1 capable, capture streams need
+	 * pause push/release to be disabled
+	 */
+	if (hda_always_enable_dmi_l1 && direction == SNDRV_PCM_STREAM_CAPTURE)
+		runtime->hw.info &= ~SNDRV_PCM_INFO_PAUSE;
+
+	if (hda_always_enable_dmi_l1 ||
 	    spcm->stream[substream->stream].d0i3_compatible)
 		flags |= SOF_HDA_STREAM_DMI_L1_COMPATIBLE;
 
-- 
2.25.1

Re: [PATCH v2 0/4] ASoC: SOF: Intel: DMI L1 power optimization for HDaudio platforms

[Mark Brown]

On Thu, 12 Aug 2021 18:19:36 -0500, Pierre-Louis Bossart wrote:
> This patchset provides an optimization that result in significant power
> savings on Intel HDAudio platforms using SOF (Sound Open Firmware).
> 
> We previously prevented the Intel DSP from enabling the DMI_L1
> capability to work-around issues with pause on capture streams. It
> turns out that this also prevented the platform from entering high C
> states in full-duplex usages such as videoconferencing - a rather
> basic use case since the start of the pandemic.
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-next

Thanks!

[1/4] ASoC: SOF: Intel: Kconfig: clarify DMI L1 option description
      commit: 6f28c883b7ba8c611a842b4701eb4fb8bd76b70b
[2/4] ASoC: SOF: Intel: hda-stream: remove always true condition
      commit: d2556edadbf2929dd7b04de59daeb0a571dc0349
[3/4] ASoC: SOF: Intel: simplify logic for DMI_L1 handling
      commit: 5503e938fef3f66240670d28f7d5db7f2dc8f35a
[4/4] ASoC: SOF: Intel: make DMI L1 selection more robust
      commit: 246dd4287dfbaaddc1511c744893621814618bc8

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark