[alsa-devel] [PATCH 0/3] SOF: Fix HDMI probe errors on GLK devices

[alsa-devel] [PATCH 0/3] SOF: Fix HDMI probe errors on GLK devices

[Kai Vehmanen]

Hi all,
here's a patch series to address an issue that popped up
after SOF changed from hdac-hdmi to snd-hda-codec-hdmi:

"failed to get afg sub nodes on ChromeOS devices"
https://github.com/thesofproject/linux/issues/1642

This is fairly hard to hit and only occurs on some devices (most
current reports are Gemini Lake based Chromebooks), but when
it does, it is rather severe as the whole SOF probe fails
because of this, and user is left without sound.

First fix is to optimize out one power down/up cycle from
the probe process. On platforms such as GLK, each time
audio driver does acomp's get_power(), graphics typically
needs to do a modeset due to clocking requirements for the HDA
bus. This can cause display to flash when audio is probed, plus
in the reported cases on GLK, can lead to probe failures.

The above change doesn't cover all reported cases, so additionally
retry logic is added to snd_hda_get_sub_nodes() calls on
Intel platforms. Multiple other approaches were investigated,
but a simple retry -- although less than ideal -- in the end proved to
be most reliable solution. HDA dump on one affected Acer Chromebook
looks like this:

# codec initialization goes as normal with multiple successful cmds
           udevd-9486  [001] ....  3910.087791: hda_send_cmd: [0000:00:0e.0:2] val=0x207f1c00
           udevd-9486  [001] ....  3910.087857: hda_get_response: [0000:00:0e.0:2] val=0x18560010
           udevd-9486  [001] ....  3910.087858: hda_send_cmd: [0000:00:0e.0:2] val=0x207f0700
           udevd-9486  [001] ....  3910.087931: hda_get_response: [0000:00:0e.0:2] val=0x00000000
           udevd-9486  [001] ....  3910.087932: hda_send_cmd: [0000:00:0e.0:2] val=0x20bf8100
           udevd-9486  [001] ....  3910.088040: hda_get_response: [0000:00:0e.0:2] val=0x00000001
           udevd-9486  [001] ....  3910.088044: hda_send_cmd: [0000:00:0e.0:2] val=0x20b78103
# here get params for AC_PAR_NODE_COUNT fails, 0xffffffff is returned
           udevd-9486  [001] ....  3910.088048: hda_send_cmd: [0000:00:0e.0:2] val=0x201f0004
           udevd-9486  [001] ....  3911.090131: hda_get_response: [0000:00:0e.0:2] val=0xffffffff
# retry is successful
           udevd-9486  [001] ....  3911.090152: hda_send_cmd: [0000:00:0e.0:2] val=0x201f0004
           udevd-9486  [001] ....  3911.090288: hda_get_response: [0000:00:0e.0:2] val=0x00020006

Kai Vehmanen (3):
  ASoC: SOF: Intel: refactor i915_get/put functions
  ASoC: SOF: Intel: do not disable i915 power during probe
  ALSA: hda/hdmi - add retry logic to parse_intel_hdmi()

 sound/pci/hda/patch_hdmi.c      |  7 +++++--
 sound/soc/sof/intel/hda-codec.c | 21 ++++++---------------
 sound/soc/sof/intel/hda.c       |  3 ++-
 sound/soc/sof/intel/hda.h       |  7 +++----
 4 files changed, 16 insertions(+), 22 deletions(-)

-- 
2.17.1
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[alsa-devel] [PATCH 1/3] ASoC: SOF: Intel: refactor i915_get/put functions

[Kai Vehmanen]

The current interface to control i915 display power is misleading.
The hda_codec_i915_get() and hda_codec_i915_put() names suggest
a refcounting based interface. This is confusing as no refcounting
is done and the underlying HDAC library interface does not support
refcounts eithers.

Clarify the code by replacing the functions with a single
hda_codec_i915_display_power() that is aligned with
snd_hdac_display_power().

Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
---
 sound/soc/sof/intel/hda-codec.c | 21 ++++++---------------
 sound/soc/sof/intel/hda.c       |  2 +-
 sound/soc/sof/intel/hda.h       |  7 +++----
 3 files changed, 10 insertions(+), 20 deletions(-)

diff --git a/sound/soc/sof/intel/hda-codec.c b/sound/soc/sof/intel/hda-codec.c
index 827f84a0722e..55d7f6a68bc5 100644
--- a/sound/soc/sof/intel/hda-codec.c
+++ b/sound/soc/sof/intel/hda-codec.c
@@ -171,23 +171,14 @@ EXPORT_SYMBOL(hda_codec_probe_bus);
 #if IS_ENABLED(CONFIG_SND_HDA_CODEC_HDMI) || \
 	IS_ENABLED(CONFIG_SND_SOC_HDAC_HDMI)
 
-void hda_codec_i915_get(struct snd_sof_dev *sdev)
+void hda_codec_i915_display_power(struct snd_sof_dev *sdev, bool enable)
 {
 	struct hdac_bus *bus = sof_to_bus(sdev);
 
-	dev_dbg(bus->dev, "Turning i915 HDAC power on\n");
-	snd_hdac_display_power(bus, HDA_CODEC_IDX_CONTROLLER, true);
+	dev_dbg(bus->dev, "Turning i915 HDAC power %d\n", enable);
+	snd_hdac_display_power(bus, HDA_CODEC_IDX_CONTROLLER, enable);
 }
-EXPORT_SYMBOL(hda_codec_i915_get);
-
-void hda_codec_i915_put(struct snd_sof_dev *sdev)
-{
-	struct hdac_bus *bus = sof_to_bus(sdev);
-
-	dev_dbg(bus->dev, "Turning i915 HDAC power off\n");
-	snd_hdac_display_power(bus, HDA_CODEC_IDX_CONTROLLER, false);
-}
-EXPORT_SYMBOL(hda_codec_i915_put);
+EXPORT_SYMBOL_NS(hda_codec_i915_display_power, SND_SOC_SOF_HDA_AUDIO_CODEC_I915);
 
 int hda_codec_i915_init(struct snd_sof_dev *sdev)
 {
@@ -199,7 +190,7 @@ int hda_codec_i915_init(struct snd_sof_dev *sdev)
 	if (ret < 0)
 		return ret;
 
-	hda_codec_i915_get(sdev);
+	hda_codec_i915_display_power(sdev, true);
 
 	return 0;
 }
@@ -210,7 +201,7 @@ int hda_codec_i915_exit(struct snd_sof_dev *sdev)
 	struct hdac_bus *bus = sof_to_bus(sdev);
 	int ret;
 
-	hda_codec_i915_put(sdev);
+	hda_codec_i915_display_power(sdev, false);
 
 	ret = snd_hdac_i915_exit(bus);
 
diff --git a/sound/soc/sof/intel/hda.c b/sound/soc/sof/intel/hda.c
index 91bd88fddac7..efe85a4d2cd0 100644
--- a/sound/soc/sof/intel/hda.c
+++ b/sound/soc/sof/intel/hda.c
@@ -477,7 +477,7 @@ static int hda_init_caps(struct snd_sof_dev *sdev)
 	/* create codec instances */
 	hda_codec_probe_bus(sdev);
 
-	hda_codec_i915_put(sdev);
+	hda_codec_i915_display_power(sdev, false);
 
 	/*
 	 * we are done probing so decrement link counts
diff --git a/sound/soc/sof/intel/hda.h b/sound/soc/sof/intel/hda.h
index 18d7e72bf9b7..f8ebb7a3da4f 100644
--- a/sound/soc/sof/intel/hda.h
+++ b/sound/soc/sof/intel/hda.h
@@ -584,15 +584,14 @@ void hda_codec_jack_check(struct snd_sof_dev *sdev);
 	(IS_ENABLED(CONFIG_SND_HDA_CODEC_HDMI) || \
 	 IS_ENABLED(CONFIG_SND_SOC_HDAC_HDMI))
 
-void hda_codec_i915_get(struct snd_sof_dev *sdev);
-void hda_codec_i915_put(struct snd_sof_dev *sdev);
+void hda_codec_i915_display_power(struct snd_sof_dev *sdev, bool enable);
 int hda_codec_i915_init(struct snd_sof_dev *sdev);
 int hda_codec_i915_exit(struct snd_sof_dev *sdev);
 
 #else
 
-static inline void hda_codec_i915_get(struct snd_sof_dev *sdev)  { }
-static inline void hda_codec_i915_put(struct snd_sof_dev *sdev)  { }
+static inline void hda_codec_i915_display_power(struct snd_sof_dev *sdev,
+						bool enable) { }
 static inline int hda_codec_i915_init(struct snd_sof_dev *sdev) { return 0; }
 static inline int hda_codec_i915_exit(struct snd_sof_dev *sdev) { return 0; }
 
-- 
2.17.1

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[alsa-devel] [PATCH 2/3] ASoC: SOF: Intel: do not disable i915 power during probe

[Kai Vehmanen]

Change HDA probe behaviour slightly so that i915 power is not
turned off if i915 audio codecs are found in the initial probe done
by SOF Intel driver, and power is kept on until HDA codec driver
probe runs.

This will reduce number of mode sets on platforms with low
minimum CDCLK (like GLK) and brings the SOF probe sequence closer
to legacy HDA driver in terms of i915 audio codec power management.

BugLink: https://github.com/thesofproject/linux/issues/1642
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
---
 sound/soc/sof/intel/hda.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sound/soc/sof/intel/hda.c b/sound/soc/sof/intel/hda.c
index efe85a4d2cd0..a3392e6d15ab 100644
--- a/sound/soc/sof/intel/hda.c
+++ b/sound/soc/sof/intel/hda.c
@@ -477,7 +477,8 @@ static int hda_init_caps(struct snd_sof_dev *sdev)
 	/* create codec instances */
 	hda_codec_probe_bus(sdev);
 
-	hda_codec_i915_display_power(sdev, false);
+	if (!HDA_IDISP_CODEC(bus->codec_mask))
+		hda_codec_i915_display_power(sdev, false);
 
 	/*
 	 * we are done probing so decrement link counts
-- 
2.17.1

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[alsa-devel] [PATCH 3/3] ALSA: hda/hdmi - add retry logic to parse_intel_hdmi()

[Kai Vehmanen]

The initial snd_hda_get_sub_node() can fail on certain
devices (e.g. some Chromebook models using Intel GLK).
The failure rate is very low, but as this is is part of
the probe process, end-user impact is high.

In observed cases, related hardware status registers have
expected values, but the node query still fails. Retrying
the node query does seem to help, so fix the problem by
adding retry logic to the query. This does not impact
non-Intel platforms.

BugLink: https://github.com/thesofproject/linux/issues/1642
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
---
 sound/pci/hda/patch_hdmi.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
index ce3c212ee467..48bddc218829 100644
--- a/sound/pci/hda/patch_hdmi.c
+++ b/sound/pci/hda/patch_hdmi.c
@@ -2833,9 +2833,12 @@ static int alloc_intel_hdmi(struct hda_codec *codec)
 /* parse and post-process for Intel codecs */
 static int parse_intel_hdmi(struct hda_codec *codec)
 {
-	int err;
+	int err, retries = 3;
+
+	do {
+		err = hdmi_parse_codec(codec);
+	} while (err < 0 && retries--);
 
-	err = hdmi_parse_codec(codec);
 	if (err < 0) {
 		generic_spec_free(codec);
 		return err;
-- 
2.17.1

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Re: [alsa-devel] [PATCH 3/3] ALSA: hda/hdmi - add retry logic to parse_intel_hdmi()

[Takashi Iwai]

On Thu, 16 Jan 2020 15:06:10 +0100,
Kai Vehmanen wrote:
> 
> The initial snd_hda_get_sub_node() can fail on certain
> devices (e.g. some Chromebook models using Intel GLK).
> The failure rate is very low, but as this is is part of
> the probe process, end-user impact is high.
> 
> In observed cases, related hardware status registers have
> expected values, but the node query still fails. Retrying
> the node query does seem to help, so fix the problem by
> adding retry logic to the query. This does not impact
> non-Intel platforms.
> 
> BugLink: https://github.com/thesofproject/linux/issues/1642
> Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>

Looks like a less ugly workaround.
I can take this, but maybe better together with other two, so Mark,
feel free to take through your tree.

Reviewed-by: Takashi Iwai <tiwai@suse.de>


thanks,

Takashi


> ---
>  sound/pci/hda/patch_hdmi.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
> index ce3c212ee467..48bddc218829 100644
> --- a/sound/pci/hda/patch_hdmi.c
> +++ b/sound/pci/hda/patch_hdmi.c
> @@ -2833,9 +2833,12 @@ static int alloc_intel_hdmi(struct hda_codec *codec)
>  /* parse and post-process for Intel codecs */
>  static int parse_intel_hdmi(struct hda_codec *codec)
>  {
> -	int err;
> +	int err, retries = 3;
> +
> +	do {
> +		err = hdmi_parse_codec(codec);
> +	} while (err < 0 && retries--);
>  
> -	err = hdmi_parse_codec(codec);
>  	if (err < 0) {
>  		generic_spec_free(codec);
>  		return err;
> -- 
> 2.17.1
> 
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