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From: Jani Nikula <jani.nikula@linux.intel.com>
To: libin.yang@intel.com, intel-gfx@lists.freedesktop.org,
	ville.syrjala@linux.intel.com, daniel.vetter@intel.com,
	tiwai@suse.de
Subject: Re: [PATCH] drm/i915/audio: fix hdmi audio noise issue
Date: Wed, 09 Nov 2016 12:59:04 +0200	[thread overview]
Message-ID: <877f8chqbr.fsf@intel.com> (raw)
In-Reply-To: <1478680049-50757-1-git-send-email-libin.yang@intel.com>

On Wed, 09 Nov 2016, libin.yang@intel.com wrote:
> From: Libin Yang <libin.yang@intel.com>
>
> This issue is caused by:
> 6014ac12: drm/i915/audio: set proper N/M in modeset
>
> Some special 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 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@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_audio.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c
> index 813fd74..a472d35 100644
> --- a/drivers/gpu/drm/i915/intel_audio.c
> +++ b/drivers/gpu/drm/i915/intel_audio.c
> @@ -332,6 +332,13 @@ hsw_hdmi_audio_config_update(struct intel_crtc *intel_crtc, enum port port,
>  	int n;
>  	u32 tmp;
>  
> +	/* reset CTS value to 0 */
> +	tmp = I915_READ(HSW_AUD_M_CTS_ENABLE(pipe));
> +	tmp &= ~AUD_CONFIG_M_MASK;
> +	tmp &= ~AUD_M_CTS_M_VALUE_INDEX;
> +	tmp |= AUD_M_CTS_M_PROG_ENABLE;
> +	I915_WRITE(HSW_AUD_M_CTS_ENABLE(pipe), tmp);
> +
>  	tmp = I915_READ(HSW_AUD_CFG(pipe));
>  	tmp &= ~AUD_CONFIG_N_VALUE_INDEX;
>  	tmp &= ~AUD_CONFIG_PIXEL_CLOCK_HDMI_MASK;
> @@ -351,10 +358,12 @@ 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_VALUE_INDEX;
> -	tmp |= AUD_M_CTS_M_PROG_ENABLE;
> +	tmp &= ~AUD_M_CTS_M_PROG_ENABLE;
>  	I915_WRITE(HSW_AUD_M_CTS_ENABLE(pipe), tmp);

Is it necessary to do the HSW_AUD_M_CTS_ENABLE updates in two places?
Why do you both enable and disable AUD_M_CTS_M_PROG_ENABLE bit here?

BR,
Jani.


>  }

-- 
Jani Nikula, Intel Open Source Technology Center
_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

  parent reply	other threads:[~2016-11-09 10:59 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-09  8:27 [PATCH] drm/i915/audio: fix hdmi audio noise issue libin.yang
2016-11-09  9:16 ` ✓ Fi.CI.BAT: success for " Patchwork
2016-11-09 10:59 ` Jani Nikula [this message]
2016-11-10  1:48   ` [PATCH] " Yang, Libin

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