Re: [PATCH 2/4] drm/i915/skl: Read sink supported rates from edp panel

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

On Sat, Feb 21, 2015 at 11:12:11AM +0530, Sonika Jindal wrote:
> v2: Using DP_SUPPORTED_LINK_RATES macro for supported_rates array (Satheesh).
> v3: Reading dpcd's supported link rates tables based upon edp version in the
> same patch.
> v4: Move version check under is_edp (Satheesh)
> v5: Using le16 for rates, some naming, and removing nested if block (Ville)
> v6: Correctly using DP_MAX_SUPPORTED_RATES and removing DP_SUPPORTED_LINK_RATES
> (Ville)
> v7: Incorrectly removed DP_SUPPORTED_LINK_RATES in v6, re-adding it
> 
> Signed-off-by: Sonika Jindal <sonika.jindal@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_dp.c  |   38 ++++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/intel_drv.h |    1 +
>  2 files changed, 39 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 42ac99f..72deac6 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -1116,6 +1116,33 @@ hsw_dp_set_ddi_pll_sel(struct intel_crtc_state *pipe_config, int link_bw)
>  	}
>  }
>  
> +static int
> +intel_read_sink_rates(struct intel_dp *intel_dp, uint32_t *sink_rates)
> +{
> +	struct drm_device *dev = intel_dp_to_dev(intel_dp);
> +	int i = 0;
> +	uint16_t val;
> +
> +	if (INTEL_INFO(dev)->gen >= 9 && intel_dp->supported_rates[0]) {
> +		/*
> +		 * Receiver supports only main-link rate selection by
> +		 * link rate table method, so read link rates from
> +		 * supported_link_rates
> +		 */
> +		for (i = 0; i < DP_MAX_SUPPORTED_RATES; ++i) {
> +			val = le16_to_cpu(intel_dp->supported_rates[i]);
> +			if (val == 0)
> +				break;
> +
> +			sink_rates[i] = val * 200;
> +		}
> +
> +		if (i <= 0)
> +			DRM_ERROR("No rates in SUPPORTED_LINK_RATES");
> +	}
> +	return i;
> +}
> +
>  static void
>  intel_dp_set_clock(struct intel_encoder *encoder,
>  		   struct intel_crtc_state *pipe_config, int link_bw)
> @@ -3592,6 +3619,7 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
>  	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
>  	struct drm_device *dev = dig_port->base.base.dev;
>  	struct drm_i915_private *dev_priv = dev->dev_private;
> +	uint8_t rev;
>  
>  	if (intel_dp_dpcd_read_wake(&intel_dp->aux, 0x000, intel_dp->dpcd,
>  				    sizeof(intel_dp->dpcd)) < 0)
> @@ -3623,6 +3651,16 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
>  	} else
>  		intel_dp->use_tps3 = false;
>  
> +	/* Intermediate frequency support */
> +	if (is_edp(intel_dp) &&
> +	    (intel_dp->dpcd[DP_EDP_CONFIGURATION_CAP] &	DP_DPCD_DISPLAY_CONTROL_CAPABLE) &&
> +	    intel_dp_dpcd_read_wake(&intel_dp->aux, DP_EDP_DPCD_REV, &rev, 1) &&

intel_dp_dpcd_read_wake() == 1
would be the right thing to check I think.

With that fixed:
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> +	    (rev >= 0x03)) { /* eDp v1.4 or higher */
> +		intel_dp_dpcd_read_wake(&intel_dp->aux,
> +				DP_SUPPORTED_LINK_RATES,
> +				intel_dp->supported_rates,
> +				sizeof(intel_dp->supported_rates));
> +	}
>  	if (!(intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] &
>  	      DP_DWN_STRM_PORT_PRESENT))
>  		return true; /* native DP sink */
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 6832eb8..24e5411 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -602,6 +602,7 @@ struct intel_dp {
>  	uint8_t dpcd[DP_RECEIVER_CAP_SIZE];
>  	uint8_t psr_dpcd[EDP_PSR_RECEIVER_CAP_SIZE];
>  	uint8_t downstream_ports[DP_MAX_DOWNSTREAM_PORTS];
> +	__le16 supported_rates[DP_MAX_SUPPORTED_RATES];
>  	struct drm_dp_aux aux;
>  	uint8_t train_set[4];
>  	int panel_power_up_delay;
> -- 
> 1.7.10.4

-- 
Ville Syrjälä
Intel OTC
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