Re: [Intel-gfx] [PATCH 3/4] drm/i915: Remove DP_PORT_EN stuff from link training code

[Imre Deak <imre.deak@intel.com>]

On Thu, Sep 30, 2021 at 04:43:09PM +0300, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> 
> Setting DP_PORT_EN in intel_dp->DP is already handled by
> intel_dp_enable_port() so there is no point in setting it also
> from the link training code.
> 
> For DDI platforms a bit with that name doesn't even exist. The
> counterpart is DDI_BUF_CTL_ENABLE, which is already set up by
> intel_ddi_prepare_link_retrain(). Fortunately it is the same bit
> so there was no harm in doing this from the platform independent
> code as well. But it's just confusing when platform independent
> code sets platform specific bits in intel_dp->DP. Just get rid
> of it.
> 
> Cc: Imre Deak <imre.deak@intel.com>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Reviewed-by: Imre Deak <imre.deak.intel.com>

On pre-DDI platforms intel_dp_enable_port() may not be called before
short HPD/link-retraining, but the init/resume time HW readout will
set DP_PORT_EN for that case.

> ---
>  drivers/gpu/drm/i915/display/intel_dp_link_training.c | 2 --
>  1 file changed, 2 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 449499a5c4c1..053ed9302cda 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> @@ -499,8 +499,6 @@ intel_dp_prepare_link_train(struct intel_dp *intel_dp,
>  		DP_SET_ANSI_128B132B : DP_SET_ANSI_8B10B;
>  	drm_dp_dpcd_write(&intel_dp->aux, DP_DOWNSPREAD_CTRL, link_config, 2);
>  
> -	intel_dp->DP |= DP_PORT_EN;
> -
>  	return true;
>  }
>  
> -- 
> 2.32.0
>