[Intel-gfx] [PATCH v3] drm/i915/audio: fix hdmi audio noise issue

[Jani Nikula]

On Fri, 11 Nov 2016, libin.yang at intel.com wrote:
> From: Libin Yang <libin.yang at intel.com>
>
> Some monitors will have noise or even no sound after
> applying the patch 6014ac12.
>
> In patch 6014ac12, it will reset the cts value to 0 for HDMI.
> However, we need to disable Enable CTS or M Prog bit. This is
> the initial setting after HW reset.
>
> Fixes: 6014ac122ed0 ("drm/i915/audio: set proper N/M in modeset")
> Signed-off-by: Libin Yang <libin.yang at intel.com>

Pushed to dinq, thanks for the patch.

BR,
Jani.

> ---
>  drivers/gpu/drm/i915/intel_audio.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c
> index 195223d..88ed869 100644
> --- a/drivers/gpu/drm/i915/intel_audio.c
> +++ b/drivers/gpu/drm/i915/intel_audio.c
> @@ -351,10 +351,13 @@ hsw_hdmi_audio_config_update(struct intel_crtc *intel_crtc, enum port port,
>  
>  	I915_WRITE(HSW_AUD_CFG(pipe), tmp);
>  
> +	/*
> +	 * Let's disable "Enable CTS or M Prog bit"
> +	 * and let HW calculate the value
> +	 */
>  	tmp = I915_READ(HSW_AUD_M_CTS_ENABLE(pipe));
> -	tmp &= ~AUD_CONFIG_M_MASK;
> +	tmp &= ~AUD_M_CTS_M_PROG_ENABLE;
>  	tmp &= ~AUD_M_CTS_M_VALUE_INDEX;
> -	tmp |= AUD_M_CTS_M_PROG_ENABLE;
>  	I915_WRITE(HSW_AUD_M_CTS_ENABLE(pipe), tmp);
>  }

-- 
Jani Nikula, Intel Open Source Technology Center