Re: [Intel-gfx] [PATCH 1/4] drm/i915/display/hsw+: Do not program the same vswing entry twice

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Thu, May 28, 2020 at 01:03:53PM -0700, José Roberto de Souza wrote:
> It will be programed right before the link training, so no need to do
> it twice.
> It will not strictly follow BSpec sequences but most of this sequences
> are not matching anyways.
> 
> Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c | 19 ++++---------------
>  1 file changed, 4 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index aa22465bb56e..c100efc6a2c4 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -3115,7 +3115,6 @@ static void tgl_ddi_pre_enable_dp(struct intel_atomic_state *state,
>  	enum phy phy = intel_port_to_phy(dev_priv, encoder->port);
>  	struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
>  	bool is_mst = intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DP_MST);
> -	int level = intel_ddi_dp_level(intel_dp);
>  	enum transcoder transcoder = crtc_state->cpu_transcoder;
>  
>  	intel_dp_set_link_params(intel_dp, crtc_state->port_clock,
> @@ -3190,9 +3189,10 @@ static void tgl_ddi_pre_enable_dp(struct intel_atomic_state *state,
>  	 * down this function.
>  	 */
>  
> -	/* 7.e Configure voltage swing and related IO settings */
> -	tgl_ddi_vswing_sequence(encoder, crtc_state->port_clock, level,
> -				encoder->type);
> +	/*
> +	 * 7.e Configure voltage swing and related IO settings
> +	 * It will be done in intel_dp_start_link_train(), no need to do twice
> +	 */

Hmm. Do we still set it up before turning on the port?

>  
>  	/*
>  	 * 7.f Combo PHY: Configure PORT_CL_DW10 Static Power Down to power up
> @@ -3257,7 +3257,6 @@ static void hsw_ddi_pre_enable_dp(struct intel_atomic_state *state,
>  	enum phy phy = intel_port_to_phy(dev_priv, port);
>  	struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
>  	bool is_mst = intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DP_MST);
> -	int level = intel_ddi_dp_level(intel_dp);
>  
>  	if (INTEL_GEN(dev_priv) < 11)
>  		drm_WARN_ON(&dev_priv->drm,
> @@ -3279,16 +3278,6 @@ static void hsw_ddi_pre_enable_dp(struct intel_atomic_state *state,
>  
>  	icl_program_mg_dp_mode(dig_port, crtc_state);
>  
> -	if (INTEL_GEN(dev_priv) >= 11)
> -		icl_ddi_vswing_sequence(encoder, crtc_state->port_clock,
> -					level, encoder->type);
> -	else if (IS_CANNONLAKE(dev_priv))
> -		cnl_ddi_vswing_sequence(encoder, level, encoder->type);
> -	else if (IS_GEN9_LP(dev_priv))
> -		bxt_ddi_vswing_sequence(encoder, level, encoder->type);
> -	else
> -		intel_prepare_dp_ddi_buffers(encoder, crtc_state);

This last one definitely has to stay IIRC. HSW/BDW/SKL buf trans
stuff works quite bit differently than the BXT+ style more manual
programming.

> -
>  	if (intel_phy_is_combo(dev_priv, phy)) {
>  		bool lane_reversal =
>  			dig_port->saved_port_bits & DDI_BUF_PORT_REVERSAL;
> -- 
> 2.26.2
> 
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-- 
Ville Syrjälä
Intel
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