[PATCH v7 5/6] drm/i915: enable scrambling

Ander Conselvan De Oliveira conselvan2 at gmail.com
Tue Mar 7 10:12:45 UTC 2017


On Fri, 2017-03-03 at 21:58 +0530, Shashank Sharma wrote:
> Geminilake platform sports a native HDMI 2.0 controller, and is
> capable of driving pixel-clocks upto 594Mhz. HDMI 2.0 spec
> mendates scrambling for these higher clocks, for reduced RF footprint.
> 
> This patch checks if the monitor supports scrambling, and if required,
> enables it during the modeset.
> 
> V2: Addressed review comments from Ville:
> - Do not track scrambling status in DRM layer, track somewhere in
>   driver like in intel_crtc_state.
> - Don't talk to monitor at such a low layer, set monitor scrambling
>   in intel_enable_ddi() before enabling the port.
> 
> V3: Addressed review comments from Jani
>  - In comments, function names, use "sink" instead of "monitor",
>    so that the implementation could be close to the language of
>    HDMI spec.
> 
> V4: Addressed review comment from Maarten
>  - scrambling -> hdmi_scrambling
>    high_tmds_clock_ratio -> hdmi_high_tmds_clock_ratio
> 
> V5: Addressed review comments from Ville and Ander
>  - Do not modifiy the crtc_state after compute_config. Move all
>    scrambling and tmds_clock_ratio calcutations to compute_config.
>  - While setting scrambling for source/sink, do not check the
>    conditions again, just go by the crtc_state flags. This will
>    simplyfy the condition checks.
> 
> V6: Addressed review comments from Ville
>  - Do not add IS_GLK check in disable/enable function, instead add it
>    in compute_config, while setting state flags.
>  - Remove unnecessary paranthesis.
>  - Simplyfy handle_sink_scrambling function as suggested.
>  - Add readout code for scrambling status in get_ddi_config and add a
>    check for the same in pipe_config_compare.
> 
> V7: Addressed review comments from Ander/Ville
>  - No separate function for source scrambling, make it inline
>  - Align the last line of the macro TRANS_DDI_HDMI_SCRAMBLING_MASK
>  - Do not add platform check while setting source scrambling
>  - Use pipe_config instead of crtc->config to set sink scrambling
>  - To readout scrambling status, Compare with SCRAMBLING_MASK
>    not any of its bits
>  - Remove platform check in intel_pipe_config_compare while checking
>    scrambling status
> 
> Signed-off-by: Shashank Sharma <shashank.sharma at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_reg.h      |  7 +++++
>  drivers/gpu/drm/i915/intel_ddi.c     | 33 +++++++++++++++++++++++
>  drivers/gpu/drm/i915/intel_display.c |  3 +++
>  drivers/gpu/drm/i915/intel_drv.h     | 10 +++++++
>  drivers/gpu/drm/i915/intel_hdmi.c    | 52 ++++++++++++++++++++++++++++++++++++
>  5 files changed, 105 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 4906ce4d..bfd988b 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -7824,7 +7824,14 @@ enum {
>  #define  TRANS_DDI_EDP_INPUT_B_ONOFF	(5<<12)
>  #define  TRANS_DDI_EDP_INPUT_C_ONOFF	(6<<12)
>  #define  TRANS_DDI_DP_VC_PAYLOAD_ALLOC	(1<<8)
> +#define  TRANS_DDI_HDMI_SCRAMBLER_CTS_ENABLE (1<<7)
> +#define  TRANS_DDI_HDMI_SCRAMBLER_RESET_FREQ (1<<6)
>  #define  TRANS_DDI_BFI_ENABLE		(1<<4)
> +#define  TRANS_DDI_HIGH_TMDS_CHAR_RATE	(1<<4)
> +#define  TRANS_DDI_HDMI_SCRAMBLING	(1<<0)
> +#define  TRANS_DDI_HDMI_SCRAMBLING_MASK (TRANS_DDI_HDMI_SCRAMBLER_CTS_ENABLE \
> +					| TRANS_DDI_HDMI_SCRAMBLER_RESET_FREQ \
> +					| TRANS_DDI_HDMI_SCRAMBLING)
>  
>  /* DisplayPort Transport Control */
>  #define _DP_TP_CTL_A			0x64040
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index a7c08d7..2159b2b 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -1311,6 +1311,11 @@ void intel_ddi_enable_transcoder_func(struct drm_crtc *crtc)
>  			temp |= TRANS_DDI_MODE_SELECT_HDMI;
>  		else
>  			temp |= TRANS_DDI_MODE_SELECT_DVI;
> +
> +		if (intel_crtc->config->hdmi_scrambling)
> +			temp |= TRANS_DDI_HDMI_SCRAMBLING_MASK;
> +		if (intel_crtc->config->hdmi_high_tmds_clock_ratio)
> +			temp |= TRANS_DDI_HIGH_TMDS_CHAR_RATE;
>  	} else if (type == INTEL_OUTPUT_ANALOG) {
>  		temp |= TRANS_DDI_MODE_SELECT_FDI;
>  		temp |= (intel_crtc->config->fdi_lanes - 1) << 1;
> @@ -1885,6 +1890,20 @@ static void intel_enable_ddi(struct intel_encoder *intel_encoder,
>  		struct intel_digital_port *intel_dig_port =
>  			enc_to_dig_port(encoder);
>  
> +		if (IS_GEMINILAKE(dev_priv)) {
> +			/*
> +			 * GLK sports a native HDMI 2.0 controller. If required
> +			 * clock rate is > 340 Mhz && scrambling is supported
> +			 * by sink, enable scrambling before enabling the
> +			 * HDMI 2.0 port. The sink can choose to disable the
> +			 * scrambling if it doesn't detect a scrambled within
> +			 * 100 ms.
> +			 */

This comment seems out of place, it explains what's the effect of calling
intel_hdmi_handle_sink_scrambling(). That should be in that function's kernel
doc instead, which I now realize is missing.

> +			intel_hdmi_handle_sink_scrambling(intel_encoder,
> +						conn_state->connector,
> +						pipe_config, true);
> +		}
> +
>  		/* In HDMI/DVI mode, the port width, and swing/emphasis values
>  		 * are ignored so nothing special needs to be done besides
>  		 * enabling the port.
> @@ -1917,6 +1936,14 @@ static void intel_disable_ddi(struct intel_encoder *intel_encoder,
>  	if (old_crtc_state->has_audio)
>  		intel_audio_codec_disable(intel_encoder);
>  
> +	if (type == INTEL_OUTPUT_HDMI) {
> +		struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
> +
> +		intel_hdmi_handle_sink_scrambling(intel_encoder,
> +					old_conn_state->connector,
> +					intel_crtc->config, false);

I'm wondering if this should old_crtc_state instead? If I remember right,
crtc_state fields that are not explicitly preserved are zeroed, so
handle_sink_scrambling() won't actually disable scrambling here.

Also, there's an asymmetry between this and the enable path, since that checks
for IS_GEMINILAKE() and this doesn't. Would it make sense to move the check into
intel_hdmi_handle_sink_scrambling()? Ville?


> +	}
> +
>  	if (type == INTEL_OUTPUT_EDP) {
>  		struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
>  
> @@ -2044,6 +2071,12 @@ void intel_ddi_get_config(struct intel_encoder *encoder,
>  
>  		if (intel_hdmi->infoframe_enabled(&encoder->base, pipe_config))
>  			pipe_config->has_infoframe = true;
> +
> +		if ((temp & TRANS_DDI_HDMI_SCRAMBLING_MASK) ==
> +				TRANS_DDI_HDMI_SCRAMBLING_MASK)

This is misaligned.

Ander

> +			pipe_config->hdmi_scrambling = true;
> +		if (temp & TRANS_DDI_HIGH_TMDS_CHAR_RATE)
> +			pipe_config->hdmi_high_tmds_clock_ratio = true;
>  		/* fall through */
>  	case TRANS_DDI_MODE_SELECT_DVI:
>  		pipe_config->lane_count = 4;
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 99e8d9c..21d64c0 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -11662,6 +11662,9 @@ static void __printf(3, 4)
>  	if ((INTEL_GEN(dev_priv) < 8 && !IS_HASWELL(dev_priv)) ||
>  	    IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
>  		PIPE_CONF_CHECK_I(limited_color_range);
> +
> +	PIPE_CONF_CHECK_I(hdmi_scrambling);
> +	PIPE_CONF_CHECK_I(hdmi_high_tmds_clock_ratio);
>  	PIPE_CONF_CHECK_I(has_infoframe);
>  
>  	PIPE_CONF_CHECK_I(has_audio);
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index e6fbbee..62fbeb2 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -695,6 +695,12 @@ struct intel_crtc_state {
>  
>  	/* Gamma mode programmed on the pipe */
>  	uint32_t gamma_mode;
> +
> +	/* HDMI scrambling status (sink) */
> +	bool hdmi_scrambling;
> +
> +	/* HDMI High TMDS char rate ratio (sink) */
> +	bool hdmi_high_tmds_clock_ratio;
>  };
>  
>  struct vlv_wm_state {
> @@ -1626,6 +1632,10 @@ void intel_hdmi_init_connector(struct intel_digital_port *intel_dig_port,
>  bool intel_hdmi_compute_config(struct intel_encoder *encoder,
>  			       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,
> +					struct intel_crtc_state *config,
> +					bool enable);
>  void intel_dp_dual_mode_set_tmds_output(struct intel_hdmi *hdmi, bool enable);
>  
>  
> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> index c2184f7..c6e2398 100644
> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> @@ -34,6 +34,7 @@
>  #include <drm/drm_atomic_helper.h>
>  #include <drm/drm_crtc.h>
>  #include <drm/drm_edid.h>
> +#include <drm/drm_scdc_helper.h>
>  #include "intel_drv.h"
>  #include <drm/i915_drm.h>
>  #include <drm/intel_lpe_audio.h>
> @@ -1316,6 +1317,7 @@ bool intel_hdmi_compute_config(struct intel_encoder *encoder,
>  	struct intel_hdmi *intel_hdmi = enc_to_intel_hdmi(&encoder->base);
>  	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
>  	struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
> +	struct drm_scdc *scdc = &conn_state->connector->display_info.hdmi.scdc;
>  	int clock_8bpc = pipe_config->base.adjusted_mode.crtc_clock;
>  	int clock_12bpc = clock_8bpc * 3 / 2;
>  	int desired_bpp;
> @@ -1385,6 +1387,16 @@ bool intel_hdmi_compute_config(struct intel_encoder *encoder,
>  
>  	pipe_config->lane_count = 4;
>  
> +	if (scdc->scrambling.supported && IS_GEMINILAKE(dev_priv)) {
> +		if (scdc->scrambling.low_rates)
> +			pipe_config->hdmi_scrambling = true;
> +
> +		if (pipe_config->port_clock > 340000) {
> +			pipe_config->hdmi_scrambling = true;
> +			pipe_config->hdmi_high_tmds_clock_ratio = true;
> +		}
> +	}
> +
>  	return true;
>  }
>  
> @@ -1794,6 +1806,46 @@ static void intel_hdmi_destroy(struct drm_connector *connector)
>  	intel_hdmi->aspect_ratio = HDMI_PICTURE_ASPECT_NONE;
>  }
> 
> +void intel_hdmi_handle_sink_scrambling(struct intel_encoder *intel_encoder,
> +				       struct drm_connector *connector,
> +				       struct intel_crtc_state *config,
> +				       bool enable)
> +{
> +	struct intel_hdmi *intel_hdmi = enc_to_intel_hdmi(&intel_encoder->base);
> +	struct drm_i915_private *dev_priv = connector->dev->dev_private;
> +	struct drm_scrambling *scrambling =
> +				&connector->display_info.hdmi.scdc.scrambling;
> +	struct i2c_adapter *adptr = intel_gmbus_get_adapter(dev_priv,
> +							  intel_hdmi->ddc_bus);
> +	bool ret;
> +
> +	if (!scrambling->supported)
> +		return;
> +
> +	DRM_DEBUG_KMS("Setting sink scrambling for enc:%s connector:%s\n",
> +			intel_encoder->base.name, connector->name);
> +
> +	if (config->hdmi_high_tmds_clock_ratio) {
> +		/* Set TMDS bit clock ratio to 1/40 or 1/10 */
> +		ret = drm_scdc_set_high_tmds_clock_ratio(adptr, enable);
> +		if (!ret) {
> +			DRM_ERROR("Set TMDS ratio failed\n");
> +			return;
> +		}
> +	}
> +
> +	if (config->hdmi_scrambling) {
> +		/* Enable/disable sink scrambling */
> +		ret = drm_scdc_set_scrambling(adptr, enable);
> +		if (!ret) {
> +			DRM_ERROR("Set sink scrambling failed\n");
> +			return;
> +		}
> +	}
> +
> +	DRM_DEBUG_KMS("sink scrambling handled\n");
> +}
> +
>  static u8 intel_hdmi_ddc_pin(struct drm_i915_private *dev_priv,
>  			     enum port port)
>  {


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