Re: [PATCH 01/09] drm/i915: move common code to intel_dp_set_link_train

[Daniel Vetter <daniel@ffwll.ch>]

On Fri, Jun 29, 2012 at 04:03:33PM -0300, Paulo Zanoni wrote:
> From: Paulo Zanoni <paulo.r.zanoni@intel.com>
> 
> IMHO, that code really belongs to intel_dp_set_link_train. The caller
> functions are also big, so now they'll be a little bit easier to read.

I've gotten rather confused with this patch until I've figure out what
you're actually doing. I think it'd be nice to explain what you mean by
"common code" exactly. What about adding:

- Change set_link_train to also do the right thing when disabling link
  training so that it can be used in the complete_link_train function.
- Don adjust the DP_CTL value in the caller, instead select the right
  bitmask for the desired training pattern according to dp_train_pat.

Yours, Daniel

> 
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_dp.c |   77 ++++++++++++++++++++++++---------------
>  1 file changed, 47 insertions(+), 30 deletions(-)
> 
> We'll add even more code to intel_dp_set_link_train on Haswell.
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 76a7080..e315f73 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -1672,6 +1672,41 @@ intel_dp_set_link_train(struct intel_dp *intel_dp,
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  	int ret;
>  
> +	if (HAS_PCH_CPT(dev) && (IS_GEN7(dev) || !is_cpu_edp(intel_dp))) {
> +		switch (dp_train_pat & DP_TRAINING_PATTERN_MASK) {
> +		case DP_TRAINING_PATTERN_DISABLE:
> +			dp_reg_value |= DP_LINK_TRAIN_OFF_CPT;
> +			break;
> +		case DP_TRAINING_PATTERN_1:
> +			dp_reg_value |= DP_LINK_TRAIN_PAT_1_CPT;
> +			break;
> +		case DP_TRAINING_PATTERN_2:
> +			dp_reg_value |= DP_LINK_TRAIN_PAT_2_CPT;
> +			break;
> +		case DP_TRAINING_PATTERN_3:
> +			DRM_ERROR("DP training pattern 3 not supported\n");
> +			dp_reg_value |= DP_LINK_TRAIN_PAT_2_CPT;
> +			break;
> +		}
> +
> +	} else {
> +		switch (dp_train_pat & DP_TRAINING_PATTERN_MASK) {
> +		case DP_TRAINING_PATTERN_DISABLE:
> +			dp_reg_value |= DP_LINK_TRAIN_OFF;
> +			break;
> +		case DP_TRAINING_PATTERN_1:
> +			dp_reg_value |= DP_LINK_TRAIN_PAT_1;
> +			break;
> +		case DP_TRAINING_PATTERN_2:
> +			dp_reg_value |= DP_LINK_TRAIN_PAT_2;
> +			break;
> +		case DP_TRAINING_PATTERN_3:
> +			DRM_ERROR("DP training pattern 3 not supported\n");
> +			dp_reg_value |= DP_LINK_TRAIN_PAT_2;
> +			break;
> +		}
> +	}
> +
>  	I915_WRITE(intel_dp->output_reg, dp_reg_value);
>  	POSTING_READ(intel_dp->output_reg);
>  
> @@ -1679,12 +1714,15 @@ intel_dp_set_link_train(struct intel_dp *intel_dp,
>  				    DP_TRAINING_PATTERN_SET,
>  				    dp_train_pat);
>  
> -	ret = intel_dp_aux_native_write(intel_dp,
> -					DP_TRAINING_LANE0_SET,
> -					intel_dp->train_set,
> -					intel_dp->lane_count);
> -	if (ret != intel_dp->lane_count)
> -		return false;
> +	if ((dp_train_pat & DP_TRAINING_PATTERN_MASK) !=
> +	    DP_TRAINING_PATTERN_DISABLE) {
> +		ret = intel_dp_aux_native_write(intel_dp,
> +						DP_TRAINING_LANE0_SET,
> +						intel_dp->train_set,
> +						intel_dp->lane_count);
> +		if (ret != intel_dp->lane_count)
> +			return false;
> +	}
>  
>  	return true;
>  }
> @@ -1700,7 +1738,6 @@ intel_dp_start_link_train(struct intel_dp *intel_dp)
>  	uint8_t voltage;
>  	bool clock_recovery = false;
>  	int voltage_tries, loop_tries;
> -	u32 reg;
>  	uint32_t DP = intel_dp->DP;
>  
>  	/*
> @@ -1748,12 +1785,7 @@ intel_dp_start_link_train(struct intel_dp *intel_dp)
>  			DP = (DP & ~(DP_VOLTAGE_MASK|DP_PRE_EMPHASIS_MASK)) | signal_levels;
>  		}
>  
> -		if (HAS_PCH_CPT(dev) && (IS_GEN7(dev) || !is_cpu_edp(intel_dp)))
> -			reg = DP | DP_LINK_TRAIN_PAT_1_CPT;
> -		else
> -			reg = DP | DP_LINK_TRAIN_PAT_1;
> -
> -		if (!intel_dp_set_link_train(intel_dp, reg,
> +		if (!intel_dp_set_link_train(intel_dp, DP,
>  					     DP_TRAINING_PATTERN_1 |
>  					     DP_LINK_SCRAMBLING_DISABLE))
>  			break;
> @@ -1808,10 +1840,8 @@ static void
>  intel_dp_complete_link_train(struct intel_dp *intel_dp)
>  {
>  	struct drm_device *dev = intel_dp->base.base.dev;
> -	struct drm_i915_private *dev_priv = dev->dev_private;
>  	bool channel_eq = false;
>  	int tries, cr_tries;
> -	u32 reg;
>  	uint32_t DP = intel_dp->DP;
>  
>  	/* channel equalization */
> @@ -1840,13 +1870,8 @@ intel_dp_complete_link_train(struct intel_dp *intel_dp)
>  			DP = (DP & ~(DP_VOLTAGE_MASK|DP_PRE_EMPHASIS_MASK)) | signal_levels;
>  		}
>  
> -		if (HAS_PCH_CPT(dev) && (IS_GEN7(dev) || !is_cpu_edp(intel_dp)))
> -			reg = DP | DP_LINK_TRAIN_PAT_2_CPT;
> -		else
> -			reg = DP | DP_LINK_TRAIN_PAT_2;
> -
>  		/* channel eq pattern */
> -		if (!intel_dp_set_link_train(intel_dp, reg,
> +		if (!intel_dp_set_link_train(intel_dp, DP,
>  					     DP_TRAINING_PATTERN_2 |
>  					     DP_LINK_SCRAMBLING_DISABLE))
>  			break;
> @@ -1881,15 +1906,7 @@ intel_dp_complete_link_train(struct intel_dp *intel_dp)
>  		++tries;
>  	}
>  
> -	if (HAS_PCH_CPT(dev) && (IS_GEN7(dev) || !is_cpu_edp(intel_dp)))
> -		reg = DP | DP_LINK_TRAIN_OFF_CPT;
> -	else
> -		reg = DP | DP_LINK_TRAIN_OFF;
> -
> -	I915_WRITE(intel_dp->output_reg, reg);
> -	POSTING_READ(intel_dp->output_reg);
> -	intel_dp_aux_native_write_1(intel_dp,
> -				    DP_TRAINING_PATTERN_SET, DP_TRAINING_PATTERN_DISABLE);
> +	intel_dp_set_link_train(intel_dp, DP, DP_TRAINING_PATTERN_DISABLE);
>  }
>  
>  static void
> -- 
> 1.7.10.2
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48