[Intel-gfx] [PATCH v2 3/6] drm/i915: Factor out a helper to disable the DPCD training pattern

[Ville Syrjälä]

On Thu, Sep 24, 2020 at 09:48:02PM +0300, Imre Deak wrote:
> To prepare for a follow-up LTTPR change factor out a helper to disable
> the training pattern in DPCD. We'll need to do this for each LTTPR
> (without programming the port to output the idle pattern) when training
> in LTTPR non-transparent mode.
> 
> While at it also move the disable-link-training logic from
> intel_dp_set_link_train() to intel_dp_stop_link_train(), since the
> latter is the only user of this.
> 
> v2:
> - Move the disable-link-training logic to intel_dp_stop_link_train()
>   (Ville)
> 
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>  .../drm/i915/display/intel_dp_link_training.c | 32 +++++++++----------
>  1 file changed, 16 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> index 78b0f165fadd..38d4553670a1 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> @@ -91,25 +91,17 @@ intel_dp_set_link_train(struct intel_dp *intel_dp,
>  			u8 dp_train_pat)
>  {
>  	u8 buf[sizeof(intel_dp->train_set) + 1];
> -	int ret, len;
> +	int len;
>  
>  	intel_dp_program_link_training_pattern(intel_dp, dp_train_pat);
>  
>  	buf[0] = dp_train_pat;
> -	if (intel_dp_training_pattern_symbol(dp_train_pat) ==
> -	    DP_TRAINING_PATTERN_DISABLE) {
> -		/* don't write DP_TRAINING_LANEx_SET on disable */
> -		len = 1;
> -	} else {
> -		/* DP_TRAINING_LANEx_SET follow DP_TRAINING_PATTERN_SET */
> -		memcpy(buf + 1, intel_dp->train_set, intel_dp->lane_count);
> -		len = intel_dp->lane_count + 1;
> -	}
> +	/* DP_TRAINING_LANEx_SET follow DP_TRAINING_PATTERN_SET */
> +	memcpy(buf + 1, intel_dp->train_set, intel_dp->lane_count);
> +	len = intel_dp->lane_count + 1;
>  
> -	ret = drm_dp_dpcd_write(&intel_dp->aux, DP_TRAINING_PATTERN_SET,
> -				buf, len);
> -
> -	return ret == len;
> +	return drm_dp_dpcd_write(&intel_dp->aux, DP_TRAINING_PATTERN_SET,
> +				 buf, len) == len;

Much nicer without the silly if() cluttering things.

Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

>  }
>  
>  static bool
> @@ -392,6 +384,13 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp)
>  	return channel_eq;
>  }
>  
> +static bool intel_dp_disable_dpcd_training_pattern(struct intel_dp *intel_dp)
> +{
> +	u8 val = DP_TRAINING_PATTERN_DISABLE;
> +
> +	return drm_dp_dpcd_write(&intel_dp->aux, DP_TRAINING_PATTERN_SET, &val, 1) == 1;
> +}
> +
>  /**
>   * intel_dp_stop_link_train - stop link training
>   * @intel_dp: DP struct
> @@ -411,8 +410,9 @@ void intel_dp_stop_link_train(struct intel_dp *intel_dp)
>  {
>  	intel_dp->link_trained = true;
>  
> -	intel_dp_set_link_train(intel_dp,
> -				DP_TRAINING_PATTERN_DISABLE);
> +	intel_dp_program_link_training_pattern(intel_dp,
> +					       DP_TRAINING_PATTERN_DISABLE);
> +	intel_dp_disable_dpcd_training_pattern(intel_dp);
>  }
>  
>  static bool
> -- 
> 2.25.1

-- 
Ville Syrjälä
Intel