[Intel-gfx] [PATCH v2] drm/i915/audio: set HDA link parameters in driver

[Shankar, Uma]

> -----Original Message-----
> From: Kai Vehmanen <kai.vehmanen at linux.intel.com>
> Sent: Wednesday, March 24, 2021 6:07 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: Kai Vehmanen <kai.vehmanen at linux.intel.com>; Shankar, Uma
> <uma.shankar at intel.com>
> Subject: [PATCH v2] drm/i915/audio: set HDA link parameters in driver
> 
> Update logic to program AUD_FREQ_CNTRL register based on new guidance.
> Earlier this register was configured by BIOS and driver discovered the value at init.
> This is no longer recommended and instead driver should set the values based on the
> hardware revision.
> 
> Add the recommended values for all supported hardware. This change applies for all
> GEN12+ hardware. For TGL, some special case handling is needed to not break
> existing systems.
> 
> Extend the debug print to also include values of the register as written by BIOS. This
> can help debug rare cases where BIOS has configured the link settings to incorrect
> values.

Pushed to drm-intel-next. Thanks for the patch.

Regards,
Uma Shankar

> Bspec: 49279
> Signed-off-by: Kai Vehmanen <kai.vehmanen at linux.intel.com>
> Reviewed-by: Uma Shankar <uma.shankar at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_audio.c | 30 ++++++++++++++++++----
>  1 file changed, 25 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_audio.c
> b/drivers/gpu/drm/i915/display/intel_audio.c
> index 3ea20c857440..9671c8f6e892 100644
> --- a/drivers/gpu/drm/i915/display/intel_audio.c
> +++ b/drivers/gpu/drm/i915/display/intel_audio.c
> @@ -1266,6 +1266,15 @@ static const struct component_ops
> i915_audio_component_bind_ops = {
>  	.unbind	= i915_audio_component_unbind,
>  };
> 
> +#define AUD_FREQ_TMODE_SHIFT	14
> +#define AUD_FREQ_4T		0
> +#define AUD_FREQ_8T		(2 << AUD_FREQ_TMODE_SHIFT)
> +#define AUD_FREQ_PULLCLKS(x)	(((x) & 0x3) << 11)
> +#define AUD_FREQ_BCLK_96M	BIT(4)
> +
> +#define AUD_FREQ_GEN12          (AUD_FREQ_8T | AUD_FREQ_PULLCLKS(0) |
> AUD_FREQ_BCLK_96M)
> +#define AUD_FREQ_TGL_BROKEN     (AUD_FREQ_8T | AUD_FREQ_PULLCLKS(2) |
> AUD_FREQ_BCLK_96M)
> +
>  /**
>   * i915_audio_component_init - initialize and register the audio component
>   * @dev_priv: i915 device instance
> @@ -1284,6 +1293,7 @@ static const struct component_ops
> i915_audio_component_bind_ops = {
>   */
>  static void i915_audio_component_init(struct drm_i915_private *dev_priv)  {
> +	u32 aud_freq, aud_freq_init;
>  	int ret;
> 
>  	ret = component_add_typed(dev_priv->drm.dev,
> @@ -1297,11 +1307,21 @@ static void i915_audio_component_init(struct
> drm_i915_private *dev_priv)
>  	}
> 
>  	if (DISPLAY_VER(dev_priv) >= 9) {
> -		dev_priv->audio_freq_cntrl = intel_de_read(dev_priv,
> -							   AUD_FREQ_CNTRL);
> -		drm_dbg_kms(&dev_priv->drm,
> -			    "init value of AUD_FREQ_CNTRL of 0x%x\n",
> -			    dev_priv->audio_freq_cntrl);
> +		aud_freq_init = intel_de_read(dev_priv, AUD_FREQ_CNTRL);
> +
> +		if (INTEL_GEN(dev_priv) >= 12)
> +			aud_freq = AUD_FREQ_GEN12;
> +		else
> +			aud_freq = aud_freq_init;
> +
> +		/* use BIOS provided value for TGL unless it is a known bad value */
> +		if (IS_TIGERLAKE(dev_priv) && aud_freq_init !=
> AUD_FREQ_TGL_BROKEN)
> +			aud_freq = aud_freq_init;
> +
> +		drm_dbg_kms(&dev_priv->drm, "use AUD_FREQ_CNTRL of 0x%x
> (init value 0x%x)\n",
> +			    aud_freq, aud_freq_init);
> +
> +		dev_priv->audio_freq_cntrl = aud_freq;
>  	}
> 
>  	dev_priv->audio_component_registered = true;
> 
> base-commit: 9d58aa46291d4d696bb1eac3436d3118f7bf2573
> --
> 2.29.2