Re: [PATCH] drm/i915/tgl: Do not read the transcoder register for mipi dsi

[Jani Nikula <jani.nikula@intel.com>]

On Mon, 11 Nov 2019, Vandita Kulkarni <vandita.kulkarni@intel.com> wrote:
> As per the Bspec the port mapping is fixed for mipi dsi

The "tgl" in the patch subject is slightly confusing, because this isn't
new to tgl.

>
> Signed-off-by: Vandita Kulkarni <vandita.kulkarni@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 27 ++++++++++++++++----
>  1 file changed, 22 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index f1328c08f4ad..d4a8617d6185 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -10397,21 +10397,38 @@ static bool bxt_get_dsi_transcoder_state(struct intel_crtc *crtc,
>  	return transcoder_is_dsi(pipe_config->cpu_transcoder);
>  }
>  
> -static void haswell_get_ddi_port_state(struct intel_crtc *crtc,
> -				       struct intel_crtc_state *pipe_config)
> +static enum port
> +intel_transcoder_to_port(struct drm_i915_private *dev_priv,
> +			  enum transcoder cpu_transcoder)

This is also confusing naming because this is definitely not universal
across platforms.

>  {
> -	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
> -	struct intel_shared_dpll *pll;
>  	enum port port;
>  	u32 tmp;
>  
> -	tmp = I915_READ(TRANS_DDI_FUNC_CTL(pipe_config->cpu_transcoder));
> +	/* DSI transcoders have fixed ddi mapping*/
> +	if (transcoder_is_dsi(cpu_transcoder)) {
> +		port = (cpu_transcoder == TRANSCODER_DSI_A) ? PORT_A : PORT_B;
> +		return port;
> +	}

I think I'd just add that in the existing haswell_get_ddi_port_state()
without another function.

        if (dsi) {
        } else {

        do the below
>  
> +	tmp = I915_READ(TRANS_DDI_FUNC_CTL(cpu_transcoder));
>  	if (INTEL_GEN(dev_priv) >= 12)
>  		port = TGL_TRANS_DDI_FUNC_CTL_VAL_TO_PORT(tmp);
>  	else
>  		port = TRANS_DDI_FUNC_CTL_VAL_TO_PORT(tmp);
>  
> +	return port;
> +}
> +
> +static void haswell_get_ddi_port_state(struct intel_crtc *crtc,
> +				       struct intel_crtc_state *pipe_config)
> +{
> +	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
> +	struct intel_shared_dpll *pll;
> +	enum port port;
> +	u32 tmp;
> +
> +	port = intel_transcoder_to_port(dev_priv, pipe_config->cpu_transcoder);
> +
>  	if (INTEL_GEN(dev_priv) >= 11)
>  		icelake_get_ddi_pll(dev_priv, port, pipe_config);
>  	else if (IS_CANNONLAKE(dev_priv))

-- 
Jani Nikula, Intel Open Source Graphics Center
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