[PATCH v4 16/16] drm/i915: Enable PCON configuration for Color Conversion for TGL

[Shankar, Uma]

> -----Original Message-----
> From: Nautiyal, Ankit K <ankit.k.nautiyal at intel.com>
> Sent: Tuesday, December 8, 2020 1:22 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: dri-devel at lists.freedesktop.org; Shankar, Uma <uma.shankar at intel.com>;
> airlied at linux.ie; jani.nikula at linux.intel.com; ville.syrjala at linux.intel.com;
> Kulkarni, Vandita <vandita.kulkarni at intel.com>; Sharma, Swati2
> <swati2.sharma at intel.com>
> Subject: [PATCH v4 16/16] drm/i915: Enable PCON configuration for Color
> Conversion for TGL

Append display here.
> 
> This patch enables PCON configuration for color space conversion for
> TGL+ platfrom. This will help in supporting 8k at 60 YUV420 modes common
> in HDMI 8k panels, through a capable PCON.
> Also allow 8k at 60 YUV420 modes, only if PCON claims to support the color space
> conversion.
> 
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c | 1 +
> drivers/gpu/drm/i915/display/intel_dp.c  | 5 +++++
>  2 files changed, 6 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c
> b/drivers/gpu/drm/i915/display/intel_ddi.c
> index 721a47bbc009..ed6b8ea85408 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -3644,6 +3644,7 @@ static void tgl_ddi_pre_enable_dp(struct
> intel_atomic_state *state,
>  	if (!is_mst)
>  		intel_dp_set_power(intel_dp, DP_SET_POWER_D0);
> 
> +	intel_dp_configure_protocol_converter(intel_dp);

Both the changes seems to be unrelated, it would be good to put configuration
of protocol convertor in earlier patches and just pruning logic here.
Also the description of patch needs to change to clearly call this out.

>  	intel_dp_sink_set_decompression_state(intel_dp, crtc_state, true);
>  	/*
>  	 * DDI FEC: "anticipates enabling FEC encoding sets the FEC_READY bit
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index b3f1190d8150..86289c925612 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -720,6 +720,11 @@ intel_dp_mode_valid_downstream(struct
> intel_connector *connector,
>  	const struct drm_display_info *info = &connector->base.display_info;
>  	int tmds_clock;
> 
> +	/* Allow 8k YUV420 modes, only if PCON supports RGB->YUV conversion
> */
> +	if (mode->hdisplay == 7680 && drm_mode_is_420_only(info, mode) &&
> +	    !intel_dp->dfp.rgb_to_ycbcr)

I think this will be a platform limitation, as there may be platforms which can
do that on the SOC side as well. So would be good to limit to those platforms where
pcon conversion is the only option in order to support this configuration, instead of doing
it for all platforms.

> +		return MODE_NO_420;
> +
>  	/*
>  	 * If PCON and HDMI2.1 sink both support FRL MODE, check FRL
>  	 * bandwidth constraints.
> --
> 2.17.1