[Intel-gfx] [PATCH v2 11/13] drm/i915: Read DSC capabilities of the HDMI2.1 PCON encoder

[Shankar, Uma]

> -----Original Message-----
> From: Nautiyal, Ankit K <ankit.k.nautiyal at intel.com>
> Sent: Sunday, November 1, 2020 3:37 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: dri-devel at lists.freedesktop.org; Shankar, Uma <uma.shankar at intel.com>;
> Kulkarni, Vandita <vandita.kulkarni at intel.com>; ville.syrjala at linux.intel.com;
> Sharma, Swati2 <swati2.sharma at intel.com>
> Subject: [PATCH v2 11/13] drm/i915: Read DSC capabilities of the HDMI2.1 PCON
> encoder
> 
> This patch adds support to read and store the DSC capabilities of the
> HDMI2.1 PCon encoder. It also adds a new field to store these caps, The caps are
> read during dfp update and can later be used to get the PPS parameters for
> PCON-HDMI2.1 sink pair. Which inturn will be used to take a call to override the
> existing PPS-metadata, by either writing the entire new PPS metadata, or by
> writing only the PPS override parameters.
> 
> v2: Restructured the code to read all capability DPCDs at once and store in an
> array in intel_dp structure.
> 
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
> ---
>  .../drm/i915/display/intel_display_types.h    |  1 +
>  drivers/gpu/drm/i915/display/intel_dp.c       | 20 +++++++++++++++++++
>  2 files changed, 21 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h
> b/drivers/gpu/drm/i915/display/intel_display_types.h
> index 2c58d63928b8..f43ded030c14 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1309,6 +1309,7 @@ struct intel_dp {
>  	u8 lttpr_common_caps[DP_LTTPR_COMMON_CAP_SIZE];
>  	u8 lttpr_phy_caps[DP_MAX_LTTPR_COUNT][DP_LTTPR_PHY_CAP_SIZE];
>  	u8 fec_capable;
> +	u8 pcon_dsc_dpcd[DP_PCON_DSC_ENCODER_CAP_SIZE];
>  	/* source rates */
>  	int num_source_rates;
>  	const int *source_rates;
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index 6177169c4401..2e7ddb062efe 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -3869,6 +3869,24 @@ cpt_set_link_train(struct intel_dp *intel_dp,
>  	intel_de_posting_read(dev_priv, intel_dp->output_reg);  }
> 
> +static void intel_dp_get_pcon_dsc_cap(struct intel_dp *intel_dp) {
> +	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> +
> +	/* Clear the cached register set to avoid using stale values */
> +

Drop this extra line. With this fixed
Reviewed-by: Uma Shankar <uma.shankar at intel.com>

> +	memset(intel_dp->pcon_dsc_dpcd, 0, sizeof(intel_dp->pcon_dsc_dpcd));
> +
> +	if (drm_dp_dpcd_read(&intel_dp->aux, DP_PCON_DSC_ENCODER,
> +				     intel_dp->pcon_dsc_dpcd,
> +				     sizeof(intel_dp->pcon_dsc_dpcd)) < 0)
> +		drm_err(&i915->drm, "Failed to read DPCD register 0x%x\n",
> +			DP_PCON_DSC_ENCODER);
> +
> +	drm_dbg_kms(&i915->drm, "PCON ENCODER DSC DPCD: %*ph\n",
> +		   (int)sizeof(intel_dp->pcon_dsc_dpcd), intel_dp-
> >pcon_dsc_dpcd); }
> +
>  static int intel_dp_get_max_rate_gbps(struct intel_dp *intel_dp)  {
>  	int max_link_clock, max_lanes, max_rate_khz, max_rate_gbps; @@ -
> 6645,6 +6663,8 @@ intel_dp_update_dfp(struct intel_dp *intel_dp,
>  		    intel_dp->dfp.max_tmds_clock,
>  		    intel_dp->dfp.pcon_max_frl_bw,
>  		    intel_dp->dfp.sink_max_frl_bw);
> +
> +	intel_dp_get_pcon_dsc_cap(intel_dp);
>  }
> 
>  static void
> --
> 2.17.1