Re: [PATCH 2/3] drm/i915: grab the audio power domain when enabling audio on HSW+

[Daniel Vetter <daniel@ffwll.ch>]

On Wed, May 21, 2014 at 05:29:31PM -0300, Paulo Zanoni wrote:
> From: Paulo Zanoni <paulo.r.zanoni@intel.com>
> 
> With the current code, we unconditionally touch
> HSW_AUD_PIN_ELD_CP_VLD, which means we can touch it when the power
> well is off, and that will trigger an "Unclaimed register" message.
> 
> Just adding the intel_crtc->config.has_audio should already avoid the
> unclaimed register messsages, but since we actually need the power
> well to make the Audio code work, it makes sense to also grab the
> audio power domain reference, and release it when it's not needed
> anymore.
> 
> I used IGT's pm_rpm to reproduce this bug, but it can probably be
> reproduced on other tests that do modesets. I'm using a machine with
> eDP+HDMI connected.
> 
> Regression introduced by:
> 
> commit acfa75b02e72bad7c93564ac379712e29c001432
> Author: Daniel Vetter <daniel.vetter@ffwll.ch>
> Date:   Thu Apr 24 23:54:51 2014 +0200
>     drm/i915: Simplify audio handling on DDI ports
> 
> Credits to Daniel for suggesting this implementation.
> 
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>

Queued for -next, thanks for the patch.
-Daniel

> ---
>  drivers/gpu/drm/i915/intel_ddi.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index 355f569..b17b9c7 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -1355,6 +1355,7 @@ static void intel_enable_ddi(struct intel_encoder *intel_encoder)
>  	}
>  
>  	if (intel_crtc->config.has_audio) {
> +		intel_display_power_get(dev_priv, POWER_DOMAIN_AUDIO);
>  		tmp = I915_READ(HSW_AUD_PIN_ELD_CP_VLD);
>  		tmp |= ((AUDIO_OUTPUT_ENABLE_A | AUDIO_ELD_VALID_A) << (pipe * 4));
>  		I915_WRITE(HSW_AUD_PIN_ELD_CP_VLD, tmp);
> @@ -1372,10 +1373,15 @@ static void intel_disable_ddi(struct intel_encoder *intel_encoder)
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  	uint32_t tmp;
>  
> -	tmp = I915_READ(HSW_AUD_PIN_ELD_CP_VLD);
> -	tmp &= ~((AUDIO_OUTPUT_ENABLE_A | AUDIO_ELD_VALID_A) <<
> -		 (pipe * 4));
> -	I915_WRITE(HSW_AUD_PIN_ELD_CP_VLD, tmp);
> +	/* We can't touch HSW_AUD_PIN_ELD_CP_VLD uncionditionally because this
> +	 * register is part of the power well on Haswell. */
> +	if (intel_crtc->config.has_audio) {
> +		tmp = I915_READ(HSW_AUD_PIN_ELD_CP_VLD);
> +		tmp &= ~((AUDIO_OUTPUT_ENABLE_A | AUDIO_ELD_VALID_A) <<
> +			 (pipe * 4));
> +		I915_WRITE(HSW_AUD_PIN_ELD_CP_VLD, tmp);
> +		intel_display_power_put(dev_priv, POWER_DOMAIN_AUDIO);
> +	}
>  
>  	if (type == INTEL_OUTPUT_EDP) {
>  		struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
> -- 
> 1.9.0
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch