Re: [PATCH 18/20] drm/i915: YCBCR 420 support for LSPCON

["Sharma, Shashank" <shashank.sharma@intel.com>]

Regards

Shashank


On 7/12/2017 10:45 PM, Ville Syrjälä wrote:
> On Mon, Jul 10, 2017 at 04:48:46PM +0530, Shashank Sharma wrote:
>> LSPCON chips support YCBCR420 outputs. To be able to get
>> YCBCR420 output from LSPCON chip, the source should:
>> - Generate YCBCR444 HDMI output
>> - Set AVI infoframes for a YCBCR420 output.
>>
>> LSPCON FW gets the information from AVI infoframes, and generates
>> YCBCR420 output from a YCBCR444 input. This patch adds the necessary
>> changes to drive YCBCR420 output from LSPCON based HDMI output.
>>
>> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
>> Cc: Imre Deak <imre.deak@intel.com>
>> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
>> ---
>>   drivers/gpu/drm/i915/intel_display.c | 10 +++++++---
>>   drivers/gpu/drm/i915/intel_dp.c      | 16 +++++++++++++++-
>>   drivers/gpu/drm/i915/intel_drv.h     | 20 +++++++++++++++++---
>>   drivers/gpu/drm/i915/intel_hdmi.c    |  7 +++++--
>>   drivers/gpu/drm/i915/intel_lspcon.c  | 17 +++++++++++++++++
>>   5 files changed, 61 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
>> index c5ff568..c3c7b31 100644
>> --- a/drivers/gpu/drm/i915/intel_display.c
>> +++ b/drivers/gpu/drm/i915/intel_display.c
>> @@ -8125,9 +8125,11 @@ static void haswell_set_pipemisc(struct drm_crtc *crtc)
>>   			val |= PIPEMISC_DITHER_ENABLE | PIPEMISC_DITHER_TYPE_SP;
>>   
>>   		if (config->ycbcr420) {
>> -			val |= PIPEMISC_OUTPUT_YCBCR |
>> -				PIPEMISC_YCBCR420_ENABLE |
>> -				PIPEMISC_YCBCR420_MODE_BLEND;
>> +			val |= PIPEMISC_OUTPUT_YCBCR;
>> +
>> +			if (!config->lspcon_active)
>> +				val |= PIPEMISC_YCBCR420_ENABLE |
>> +					PIPEMISC_YCBCR420_MODE_BLEND;
>>   		}
>>   
>>   		I915_WRITE(PIPEMISC(intel_crtc->pipe), val);
>> @@ -14205,11 +14207,13 @@ static void intel_setup_outputs(struct drm_i915_private *dev_priv)
>>   		 * DDI_BUF_CTL_A or SFUSE_STRAP registers, find another way to
>>   		 * detect the ports.
>>   		 */
>> +
>>   		intel_ddi_init(dev_priv, PORT_A);
>>   		intel_ddi_init(dev_priv, PORT_B);
>>   		intel_ddi_init(dev_priv, PORT_C);
>>   
>>   		intel_dsi_init(dev_priv);
>> +
>>   	} else if (HAS_DDI(dev_priv)) {
>>   		int found;
>>   
>> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
>> index 67bc8a7a..1690aa9 100644
>> --- a/drivers/gpu/drm/i915/intel_dp.c
>> +++ b/drivers/gpu/drm/i915/intel_dp.c
>> @@ -1614,7 +1614,9 @@ intel_dp_compute_config(struct intel_encoder *encoder,
>>   	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
>>   	struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
>>   	struct intel_dp *intel_dp = enc_to_intel_dp(&encoder->base);
>> -	enum port port = dp_to_dig_port(intel_dp)->port;
>> +	struct intel_digital_port *dig_port = enc_to_dig_port(&encoder->base);
>> +	enum port port = dig_port->port;
>> +	struct intel_lspcon *lspcon = &dig_port->lspcon;
>>   	struct intel_crtc *intel_crtc = to_intel_crtc(pipe_config->base.crtc);
>>   	struct intel_connector *intel_connector = intel_dp->attached_connector;
>>   	struct intel_digital_connector_state *intel_conn_state =
>> @@ -1635,6 +1637,18 @@ intel_dp_compute_config(struct intel_encoder *encoder,
>>   	common_len = intel_dp_common_len_rate_limit(intel_dp,
>>   						    intel_dp->max_link_rate);
>>   
>> +	/* LSPCON needs special handling to drive YCBCR420 outputs */
>> +	if (lspcon->active) {
>> +		struct drm_connector *connector = &intel_connector->base;
>> +		int clock_8bpc = pipe_config->base.adjusted_mode.crtc_clock;
>> +		int clock_12bpc = clock_8bpc * 3 / 2;
>> +
>> +		pipe_config->lspcon_active = true;
>> +		pipe_config->ycbcr420 = lspcon_ycbcr420_config(connector,
>> +					     pipe_config, &clock_12bpc,
>> +					     &clock_8bpc);
> All this clock stuff here seems pointless. So I'd just replace this
> stuff with the straightforward 'pipe_config->ycbcr420 = mode_needs_420';
pipe_config->ycbcr_420 = true means we have committed into state that we 
can support this mode in YCBCR420.
But for that, we need to check connector->ycbcr420_allowed too.
Also, when the mode is 420, we need to half the clock_8bpc and clock_12bpc.

This whole stuff is happening into lspcon_ycbcr420_config function 
(which internally re-use hdmi_ycncr420_config from HDMI 2.0 series).
That's why the call is important.
>> +	}
>> +
>>   	/* No common link rates between source and sink */
>>   	WARN_ON(common_len <= 0);
>>   
>> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
>> index ed04de9..40d56f2 100644
>> --- a/drivers/gpu/drm/i915/intel_drv.h
>> +++ b/drivers/gpu/drm/i915/intel_drv.h
>> @@ -790,6 +790,9 @@ struct intel_crtc_state {
>>   
>>   	/* HDMI output type */
>>   	bool ycbcr420;
>> +
>> +	/* LSPCON is active on port */
>> +	bool lspcon_active;
>>   };
>>   
>>   struct intel_crtc {
>> @@ -1205,6 +1208,12 @@ static inline struct intel_dp *enc_to_intel_dp(struct drm_encoder *encoder)
>>   	return &enc_to_dig_port(encoder)->dp;
>>   }
>>   
>> +static inline struct intel_lspcon *
>> +enc_to_intel_lspcon(struct drm_encoder *encoder)
>> +{
>> +	return &enc_to_dig_port(encoder)->lspcon;
>> +}
>> +
>>   static inline struct intel_digital_port *
>>   dp_to_dig_port(struct intel_dp *intel_dp)
>>   {
>> @@ -1675,14 +1684,16 @@ void intel_hdmi_init_connector(struct intel_digital_port *intel_dig_port,
>>   			       struct intel_connector *intel_connector);
>>   struct intel_hdmi *enc_to_intel_hdmi(struct drm_encoder *encoder);
>>   bool intel_hdmi_compute_config(struct intel_encoder *encoder,
>> -			       struct intel_crtc_state *pipe_config,
>> -			       struct drm_connector_state *conn_state);
>> +				struct intel_crtc_state *pipe_config,
>> +				struct drm_connector_state *conn_state);
>>   void intel_hdmi_handle_sink_scrambling(struct intel_encoder *intel_encoder,
>>   				       struct drm_connector *connector,
>>   				       bool high_tmds_clock_ratio,
>>   				       bool scrambling);
>>   void intel_dp_dual_mode_set_tmds_output(struct intel_hdmi *hdmi, bool enable);
>> -
>> +bool intel_hdmi_ycbcr420_config(struct drm_connector *connector,
>> +				struct intel_crtc_state *config,
>> +				int *clock_12bpc, int *clock_8bpc);
>>   
>>   /* intel_lvds.c */
>>   void intel_lvds_init(struct drm_i915_private *dev_priv);
>> @@ -2003,6 +2014,9 @@ void intel_color_load_luts(struct drm_crtc_state *crtc_state);
>>   bool lspcon_init(struct intel_digital_port *intel_dig_port);
>>   void lspcon_resume(struct intel_lspcon *lspcon);
>>   void lspcon_wait_pcon_mode(struct intel_lspcon *lspcon);
>> +bool lspcon_ycbcr420_config(struct drm_connector *connector,
>> +			    struct intel_crtc_state *config,
>> +			    int *clock_12bpc, int *clock_8bpc);
>>   
>>   /* intel_pipe_crc.c */
>>   int intel_pipe_crc_create(struct drm_minor *minor);
>> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
>> index d1b1efc..a08ab99 100644
>> --- a/drivers/gpu/drm/i915/intel_hdmi.c
>> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
>> @@ -1362,8 +1362,7 @@ static bool hdmi_12bpc_possible(struct intel_crtc_state *crtc_state,
>>   	return true;
>>   }
>>   
>> -static bool
>> -intel_hdmi_ycbcr420_config(struct drm_connector *connector,
>> +bool intel_hdmi_ycbcr420_config(struct drm_connector *connector,
>>   			       struct intel_crtc_state *config,
>>   			       int *clock_12bpc, int *clock_8bpc)
>>   {
>> @@ -1380,6 +1379,10 @@ intel_hdmi_ycbcr420_config(struct drm_connector *connector,
>>   	*clock_8bpc /= 2;
>>   	config->ycbcr420 = true;
>>   
>> +	/* LSPCON doesn't need scaler for YCBCR420 output */
>> +	if (config->lspcon_active)
>> +		return true;
>> +
>>   	/* YCBCR 420 output conversion needs a scaler */
>>   	if (skl_update_scaler_crtc_420_output(config)) {
>>   		DRM_ERROR("Scaler allocation for output failed\n");
>> diff --git a/drivers/gpu/drm/i915/intel_lspcon.c b/drivers/gpu/drm/i915/intel_lspcon.c
>> index a350d79..f611b6d 100644
>> --- a/drivers/gpu/drm/i915/intel_lspcon.c
>> +++ b/drivers/gpu/drm/i915/intel_lspcon.c
>> @@ -202,6 +202,21 @@ static void lspcon_resume_in_pcon_wa(struct intel_lspcon *lspcon)
>>   	DRM_DEBUG_KMS("LSPCON DP descriptor mismatch after resume\n");
>>   }
>>   
>> +bool lspcon_ycbcr420_config(struct drm_connector *connector,
>> +			    struct intel_crtc_state *config,
>> +			    int *clock_12bpc, int *clock_8bpc)
>> +{
>> +	struct drm_display_info *info = &connector->display_info;
>> +	struct drm_display_mode *mode = &config->base.adjusted_mode;
>> +
>> +	if (drm_mode_is_420_only(info, mode)) {
>> +		return intel_hdmi_ycbcr420_config(connector, config,
>> +					  clock_12bpc, clock_8bpc);
>> +	}
>> +
>> +	return false;
>> +}
>> +
>>   void lspcon_resume(struct intel_lspcon *lspcon)
>>   {
>>   	enum drm_lspcon_mode expected_mode;
>> @@ -233,6 +248,7 @@ bool lspcon_init(struct intel_digital_port *intel_dig_port)
>>   	struct intel_lspcon *lspcon = &intel_dig_port->lspcon;
>>   	struct drm_device *dev = intel_dig_port->base.base.dev;
>>   	struct drm_i915_private *dev_priv = to_i915(dev);
>> +	struct drm_connector *connector = &dp->attached_connector->base;
>>   
>>   	if (!IS_GEN9(dev_priv)) {
>>   		DRM_ERROR("LSPCON is supported on GEN9 only\n");
>> @@ -264,6 +280,7 @@ bool lspcon_init(struct intel_digital_port *intel_dig_port)
>>   		return false;
>>   	}
>>   
>> +	connector->ycbcr_420_allowed = true;
>>   	drm_dp_read_desc(&dp->aux, &dp->desc, drm_dp_is_branch(dp->dpcd));
>>   
>>   	DRM_DEBUG_KMS("Success: LSPCON init\n");
>> -- 
>> 2.7.4

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