[PATCH] ALSA: hda: intel: reset link for HP ENVY 27-p014

[PATCH] ALSA: hda: intel: reset link for HP ENVY 27-p014

[Casey Tunturi via B4 Relay]

From: Casey Tunturi <casey@samaritansolutions.net>

While bringing up audio on an HP ENVY 27-p014, I found that the normal
link reset only discovers the HDMI codec. The CX20753/4 at address 0
appears after a second CRST pulse, with STATESTS left alone and no fixed
delays.

I added that pulse when address 0 is missing, and again before the codecs
resume. Initial setup uses immediate commands long enough to add the
codec, then returns the controller to CORB/RIRB.

That brought analog audio up at boot, and capture kept working through
four deep suspend and resume cycles.

Signed-off-by: Casey Tunturi <casey@samaritansolutions.net>
---
 sound/hda/controllers/intel.c | 77 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)

diff --git a/sound/hda/controllers/intel.c b/sound/hda/controllers/intel.c
index 24015c73a..0be97a46f 100644
--- a/sound/hda/controllers/intel.c
+++ b/sound/hda/controllers/intel.c
@@ -987,6 +987,46 @@ static bool azx_is_pm_ready(struct snd_card *card)
 	return true;
 }
 
+static bool hp_envy_27_needs_reset(struct azx *chip)
+{
+	struct pci_dev *pci = chip->pci;
+
+	return pci->subsystem_vendor == 0x103c &&
+	       pci->subsystem_device == 0x2b3e;
+}
+
+static u16 hp_envy_27_reset_link(struct azx *chip)
+{
+	struct hdac_bus *bus = azx_bus(chip);
+	u32 gctl;
+	u16 statests;
+	int timeout;
+
+	snd_hdac_bus_stop_chip(bus);
+
+	gctl = snd_hdac_chip_readl(bus, GCTL);
+	snd_hdac_chip_writel(bus, GCTL, gctl & ~AZX_GCTL_RESET);
+	for (timeout = 250; timeout; timeout--) {
+		if (!(snd_hdac_chip_readl(bus, GCTL) & AZX_GCTL_RESET))
+			break;
+		udelay(1);
+	}
+
+	gctl = snd_hdac_chip_readl(bus, GCTL);
+	snd_hdac_chip_writel(bus, GCTL, gctl | AZX_GCTL_RESET);
+	for (timeout = 250; timeout; timeout--) {
+		if (snd_hdac_chip_readl(bus, GCTL) & AZX_GCTL_RESET)
+			break;
+		udelay(1);
+	}
+
+	statests = snd_hdac_chip_readw(bus, STATESTS);
+	bus->codec_mask |= statests;
+	snd_hdac_bus_init_chip(bus, false);
+
+	return statests;
+}
+
 static void __azx_runtime_resume(struct azx *chip)
 {
 	struct hda_intel *hda = container_of(chip, struct hda_intel, chip);
@@ -1003,6 +1043,8 @@ static void __azx_runtime_resume(struct azx *chip)
 
 	azx_init_pci(chip);
 	hda_intel_init_chip(chip, true);
+	if (chip->pm_prepared && hp_envy_27_needs_reset(chip))
+		hp_envy_27_reset_link(chip);
 
 	/* Avoid codec resume if runtime resume is for system suspend */
 	if (!chip->pm_prepared) {
@@ -2356,6 +2398,34 @@ static const unsigned int azx_max_codecs[AZX_NUM_DRIVERS] = {
 	[AZX_DRIVER_TERA] = 1,
 };
 
+static int hp_envy_27_probe_codec(struct azx *chip)
+{
+	struct hdac_bus *bus = azx_bus(chip);
+	struct hda_codec *codec = NULL;
+	bool use_pio;
+	int probe_mask;
+	int err;
+
+	if (!hp_envy_27_needs_reset(chip) || (bus->codec_mask & BIT(0)))
+		return 0;
+	if (!(hp_envy_27_reset_link(chip) & BIT(0)))
+		return -ENODEV;
+
+	probe_mask = chip->codec_probe_mask;
+	use_pio = bus->use_pio_for_commands;
+	chip->codec_probe_mask = BIT(0);
+	bus->use_pio_for_commands = true;
+	err = snd_hda_codec_new(&chip->bus, chip->card, 0, &codec);
+	chip->codec_probe_mask = probe_mask;
+	if (!err && codec)
+		err = snd_hda_codec_configure(codec);
+	else if (!err)
+		err = -ENODEV;
+	bus->use_pio_for_commands = use_pio;
+
+	return err;
+}
+
 static int azx_probe_continue(struct azx *chip)
 {
 	struct hda_intel *hda = container_of(chip, struct hda_intel, chip);
@@ -2428,6 +2498,11 @@ static int azx_probe_continue(struct azx *chip)
 		}
 	}
 
+	err = hp_envy_27_probe_codec(chip);
+	if (err < 0 && err != -ENODEV)
+		dev_warn(chip->card->dev,
+			 "failed to probe HP ENVY 27 analog codec: %d\n", err);
+
 	err = snd_card_register(chip->card);
 	if (err < 0)
 		goto out_free;
@@ -2444,6 +2519,8 @@ static int azx_probe_continue(struct azx *chip)
 		pm_runtime_allow(&pci->dev);
 		pm_runtime_put_autosuspend(&pci->dev);
 	}
+	if (hp_envy_27_needs_reset(chip))
+		pm_runtime_forbid(&pci->dev);
 
 out_free:
 	if (err < 0) {

---
base-commit: c4a0927f535f779700d5ccda8182c2db01e9d551
change-id: 20260828-hp-envy-27-hda-reset-40651087e528

Best regards,
--  
Casey Tunturi <casey@samaritansolutions.net>

Re: [PATCH] ALSA: hda: intel: reset link for HP ENVY 27-p014

[Takashi Iwai]

On Fri, 28 Aug 2026 22:29:28 +0200,
Casey Tunturi via B4 Relay wrote:
> 
> From: Casey Tunturi <casey@samaritansolutions.net>
> 
> While bringing up audio on an HP ENVY 27-p014, I found that the normal
> link reset only discovers the HDMI codec. The CX20753/4 at address 0
> appears after a second CRST pulse, with STATESTS left alone and no fixed
> delays.
> 
> I added that pulse when address 0 is missing, and again before the codecs
> resume. Initial setup uses immediate commands long enough to add the
> codec, then returns the controller to CORB/RIRB.
> 
> That brought analog audio up at boot, and capture kept working through
> four deep suspend and resume cycles.
> 
> Signed-off-by: Casey Tunturi <casey@samaritansolutions.net>

Thanks for the patch.  But I must say that it's very hackish, and
we should reconsider to make the changes a bit more generic or
cleaner.

But, first off, could you give more details about your hardware?
At best, give alsa-info.sh output (run with --no-upload option and
attach the output).

Now more about the code change:

> +static u16 hp_envy_27_reset_link(struct azx *chip)
> +{
> +	struct hdac_bus *bus = azx_bus(chip);
> +	u32 gctl;
> +	u16 statests;
> +	int timeout;
> +
> +	snd_hdac_bus_stop_chip(bus);
> +
> +	gctl = snd_hdac_chip_readl(bus, GCTL);
> +	snd_hdac_chip_writel(bus, GCTL, gctl & ~AZX_GCTL_RESET);
> +	for (timeout = 250; timeout; timeout--) {
> +		if (!(snd_hdac_chip_readl(bus, GCTL) & AZX_GCTL_RESET))
> +			break;
> +		udelay(1);
> +	}
> +
> +	gctl = snd_hdac_chip_readl(bus, GCTL);
> +	snd_hdac_chip_writel(bus, GCTL, gctl | AZX_GCTL_RESET);
> +	for (timeout = 250; timeout; timeout--) {
> +		if (snd_hdac_chip_readl(bus, GCTL) & AZX_GCTL_RESET)
> +			break;
> +		udelay(1);
> +	}
> +
> +	statests = snd_hdac_chip_readw(bus, STATESTS);
> +	bus->codec_mask |= statests;
> +	snd_hdac_bus_init_chip(bus, false);
> +
> +	return statests;

Can't the standard snd_hdac_bus_reset_link() work?  If not, we may
tweak there in the standard code instead of open-code here.

>  static void __azx_runtime_resume(struct azx *chip)
>  {
>  	struct hda_intel *hda = container_of(chip, struct hda_intel, chip);
> @@ -1003,6 +1043,8 @@ static void __azx_runtime_resume(struct azx *chip)
>  
>  	azx_init_pci(chip);
>  	hda_intel_init_chip(chip, true);
> +	if (chip->pm_prepared && hp_envy_27_needs_reset(chip))
> +		hp_envy_27_reset_link(chip);

So you need a bus reset always at each S3/S4 resume?
Or could this be conditional?

> +static int hp_envy_27_probe_codec(struct azx *chip)
> +{
> +	struct hdac_bus *bus = azx_bus(chip);
> +	struct hda_codec *codec = NULL;
> +	bool use_pio;
> +	int probe_mask;
> +	int err;
> +
> +	if (!hp_envy_27_needs_reset(chip) || (bus->codec_mask & BIT(0)))
> +		return 0;
> +	if (!(hp_envy_27_reset_link(chip) & BIT(0)))
> +		return -ENODEV;

Trying the bus reset at probe is understandable, but...

> +	probe_mask = chip->codec_probe_mask;
> +	use_pio = bus->use_pio_for_commands;
> +	chip->codec_probe_mask = BIT(0);
> +	bus->use_pio_for_commands = true;
> +	err = snd_hda_codec_new(&chip->bus, chip->card, 0, &codec);
> +	chip->codec_probe_mask = probe_mask;
> +	if (!err && codec)
> +		err = snd_hda_codec_configure(codec);
> +	else if (!err)
> +		err = -ENODEV;
> +	bus->use_pio_for_commands = use_pio;

... those look too ugly.  The use of PIO mode isn't mentioned in the
description, either.  Maybe PIO mode should be used always for your
board?

> @@ -2444,6 +2519,8 @@ static int azx_probe_continue(struct azx *chip)
>  		pm_runtime_allow(&pci->dev);
>  		pm_runtime_put_autosuspend(&pci->dev);
>  	}
> +	if (hp_envy_27_needs_reset(chip))
> +		pm_runtime_forbid(&pci->dev);

Add to power_save_denylist, instead.


thanks,

Takashi

Re: [PATCH] ALSA: hda: intel: reset link for HP ENVY 27-p014

[Casey Tunturi]

On Tue, Sep 1, 2026 at 8:07 AM Takashi Iwai <tiwai@suse.de> wrote:
> Thanks for the patch. But I must say that it's very hackish, and we 
> should
> reconsider to make the changes a bit more generic or cleaner.
> 
> But, first off, could you give more details about your hardware? At 
> best,
> give alsa-info.sh output (run with --no-upload option and attach the 
> output).


Thank you for taking the time to review it!

Oh yes, I think it's cursed. This is a hack.

I submitted it just before leaving my in-laws' place so it wouldn't stay 
isolated to that one machine. It has been running for about four months, 
and it was the only thing I found so far that made the codec enumerate 
and gave my father-in-law working analog audio under Linux.

I don't have the machine in front of me now. I'll have it again just 
short of two weeks. I'll rerun the tests, collect the alsa-info output, 
and work through the reset and PIO questions then.

> Can't the standard snd_hdac_bus_reset_link() work? If not, we may tweak
> there in the standard code instead of open-code here.

I knew I was probably forcing the issue at the wrong layer. I asked 
around on Matrix with a couple of devs and couldn't get the standard 
reset path to work on this hardware.

I'd appreciate any pointers to code or docs I should read. I'd like to 
understand the right fix rather than just keep the workaround.

Casey