[PATCH v3 3/3] drm/i915/display: Configure HDMI2.1 Pcon for FRL only if Src-Ctl mode is available

[Shankar, Uma]

> -----Original Message-----
> From: Nautiyal, Ankit K <ankit.k.nautiyal at intel.com>
> Sent: Tuesday, March 9, 2021 10:09 AM
> To: intel-gfx at lists.freedesktop.org
> Cc: dri-devel at lists.freedesktop.org; ville.syrjala at linux.intel.com; Shankar, Uma
> <uma.shankar at intel.com>; airlied at linux.ie; jani.nikula at linux.intel.com
> Subject: [PATCH v3 3/3] drm/i915/display: Configure HDMI2.1 Pcon for FRL only if
> Src-Ctl mode is available
> 
> Currently we see only the MAX FRL BW from PCON before going for FRL.
> Also add the check if source control mode is supported by the PCON, before starting
> configuring PCON for FRL training.
> 
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index 2e90359ce21f..8e401d3fd29d 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -2638,7 +2638,8 @@ void intel_dp_check_frl_training(struct intel_dp *intel_dp)
>  	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
> 
>  	/* Always go for FRL training if supported */
> -	if (!intel_dp_is_hdmi_2_1_sink(intel_dp) ||
> +	if (!(intel_dp->dpcd[2] & DP_PCON_SOURCE_CTL_MODE) ||

Would be good to add spec reference as well here.

With that added, this is
Reviewed-by: Uma Shankar <uma.shankar at intel.com>

> +	    !intel_dp_is_hdmi_2_1_sink(intel_dp) ||
>  	    intel_dp->frl.is_trained)
>  		return;
> 
> --
> 2.29.2