Re: [PATCH] drm/i915: save AUD_FREQ_CNTRL state at audio domain suspend

[Jani Nikula <jani.nikula@intel.com>]

On Fri, 20 Sep 2019, Kai Vehmanen <kai.vehmanen@linux.intel.com> wrote:
> When audio power domain is suspended, the display driver must
> save state of AUD_FREQ_CNTRL on Tiger Lake and Ice Lake
> systems. The initial value of the register is set by BIOS and
> is read by driver during the audio component init sequence.
>
> Cc: Jani Nikula <jani.nikula@intel.com>
> Cc: Imre Deak <imre.deak@intel.com>
> Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>

Thanks for the patch, let's wait for the CI results.

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_audio.c | 17 +++++++++++++++--
>  drivers/gpu/drm/i915/i915_drv.h            |  1 +
>  drivers/gpu/drm/i915/i915_reg.h            |  2 ++
>  3 files changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_audio.c b/drivers/gpu/drm/i915/display/intel_audio.c
> index aac089c79ceb..54638d99e021 100644
> --- a/drivers/gpu/drm/i915/display/intel_audio.c
> +++ b/drivers/gpu/drm/i915/display/intel_audio.c
> @@ -852,10 +852,17 @@ static unsigned long i915_audio_component_get_power(struct device *kdev)
>  
>  	ret = intel_display_power_get(dev_priv, POWER_DOMAIN_AUDIO);
>  
> -	/* Force CDCLK to 2*BCLK as long as we need audio to be powered. */
> -	if (dev_priv->audio_power_refcount++ == 0)
> +	if (dev_priv->audio_power_refcount++ == 0) {
> +		if (IS_TIGERLAKE(dev_priv) || IS_ICELAKE(dev_priv)) {
> +			I915_WRITE(AUD_FREQ_CNTRL, dev_priv->audio_freq_cntrl);
> +			DRM_DEBUG_KMS("restored AUD_FREQ_CNTRL to 0x%x\n",
> +				      dev_priv->audio_freq_cntrl);
> +		}
> +
> +		/* Force CDCLK to 2*BCLK as long as we need audio powered. */
>  		if (IS_CANNONLAKE(dev_priv) || IS_GEMINILAKE(dev_priv))
>  			glk_force_audio_cdclk(dev_priv, true);
> +	}
>  
>  	return ret;
>  }
> @@ -1116,6 +1123,12 @@ static void i915_audio_component_init(struct drm_i915_private *dev_priv)
>  		return;
>  	}
>  
> +	if (IS_TIGERLAKE(dev_priv) || IS_ICELAKE(dev_priv)) {
> +		dev_priv->audio_freq_cntrl = I915_READ(AUD_FREQ_CNTRL);
> +		DRM_DEBUG_KMS("init value of AUD_FREQ_CNTRL of 0x%x\n",
> +			      dev_priv->audio_freq_cntrl);
> +	}
> +
>  	dev_priv->audio_component_registered = true;
>  }
>  
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 4faec2f94e19..5bb19f1c0ef4 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1540,6 +1540,7 @@ struct drm_i915_private {
>  	 */
>  	struct mutex av_mutex;
>  	int audio_power_refcount;
> +	u32 audio_freq_cntrl;
>  
>  	struct {
>  		struct mutex mutex;
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index bf37ecebc82f..dff077aa4cc6 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -9119,6 +9119,8 @@ enum {
>  #define HSW_AUD_CHICKENBIT			_MMIO(0x65f10)
>  #define   SKL_AUD_CODEC_WAKE_SIGNAL		(1 << 15)
>  
> +#define AUD_FREQ_CNTRL			_MMIO(0x65900)
> +
>  /*
>   * HSW - ICL power wells
>   *

-- 
Jani Nikula, Intel Open Source Graphics Center
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