Re: [PATCH v3 3/4] drm/i915: Enable/disable TMDS output buffers in DP++ adaptor as needed

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

On 5/3/2016 12:38 AM, ville.syrjala@linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> To save a bit of power, let's try to turn off the TMDS output buffers
> in DP++ adaptors when we're not driving the port.
>
> v2: Let's not forget DDI, toss in a debug message while at it
> v3: Just do the TMDS output control based on adaptor type. With the
>      helper getting passed the type, we wouldn't actually have to
>      check at all in the driver, but the check eliminates the debug
>      output more honest
>
> Cc: stable@vger.kernel.org
> Cc: Tore Anderson <tore@fud.no>
> Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
> Cc: Shashank Sharma <shashank.sharma@intel.com>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>   drivers/gpu/drm/i915/intel_ddi.c  | 12 ++++++++++++
>   drivers/gpu/drm/i915/intel_drv.h  |  1 +
>   drivers/gpu/drm/i915/intel_hdmi.c | 20 ++++++++++++++++++++
>   3 files changed, 33 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index 422ec81ef59b..a3600704e6d4 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -1601,6 +1601,12 @@ static void intel_ddi_pre_enable(struct intel_encoder *intel_encoder)
>   	enum port port = intel_ddi_get_encoder_port(intel_encoder);
>   	int type = intel_encoder->type;
>
> +	if (type == INTEL_OUTPUT_HDMI) {
how to handle type2 active adapters here, which can show type = DP ?
> +		struct intel_hdmi *intel_hdmi = enc_to_intel_hdmi(encoder);
> +
> +		intel_dp_dual_mode_set_tmds_output(intel_hdmi, true);
> +	}
> +
>   	intel_prepare_ddi_buffer(intel_encoder);
>
>   	if (type == INTEL_OUTPUT_EDP) {
> @@ -1667,6 +1673,12 @@ static void intel_ddi_post_disable(struct intel_encoder *intel_encoder)
>   					DPLL_CTRL2_DDI_CLK_OFF(port)));
>   	else if (INTEL_INFO(dev)->gen < 9)
>   		I915_WRITE(PORT_CLK_SEL(port), PORT_CLK_SEL_NONE);
> +
> +	if (type == INTEL_OUTPUT_HDMI) {
Same as above.

Regards
Shashank
> +		struct intel_hdmi *intel_hdmi = enc_to_intel_hdmi(encoder);
> +
> +		intel_dp_dual_mode_set_tmds_output(intel_hdmi, false);
> +	}
>   }
>
>   static void intel_enable_ddi(struct intel_encoder *intel_encoder)
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index e94d18fb2ff1..dbcb80c70e2e 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1419,6 +1419,7 @@ void intel_hdmi_init_connector(struct intel_digital_port *intel_dig_port,
>   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);
> +void intel_dp_dual_mode_set_tmds_output(struct intel_hdmi *hdmi, bool enable);
>
>
>   /* intel_lvds.c */
> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> index 31ca11134294..c4d93e6b4bed 100644
> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> @@ -836,6 +836,22 @@ static void hsw_set_infoframes(struct drm_encoder *encoder,
>   	intel_hdmi_set_hdmi_infoframe(encoder, adjusted_mode);
>   }
>
> +void intel_dp_dual_mode_set_tmds_output(struct intel_hdmi *hdmi, bool enable)
> +{
> +	struct drm_i915_private *dev_priv = to_i915(intel_hdmi_to_dev(hdmi));
> +	struct i2c_adapter *adapter =
> +		intel_gmbus_get_adapter(dev_priv, hdmi->ddc_bus);
> +
> +	if (hdmi->dp_dual_mode.type < DRM_DP_DUAL_MODE_TYPE2_DVI)
> +		return;
> +
> +	DRM_DEBUG_KMS("%s DP dual mode adaptor TMDS output\n",
> +		      enable ? "Enabling" : "Disabling");
> +
> +	drm_dp_dual_mode_set_tmds_output(hdmi->dp_dual_mode.type,
> +					 adapter, enable);
> +}
> +
>   static void intel_hdmi_prepare(struct intel_encoder *encoder)
>   {
>   	struct drm_device *dev = encoder->base.dev;
> @@ -845,6 +861,8 @@ static void intel_hdmi_prepare(struct intel_encoder *encoder)
>   	const struct drm_display_mode *adjusted_mode = &crtc->config->base.adjusted_mode;
>   	u32 hdmi_val;
>
> +	intel_dp_dual_mode_set_tmds_output(intel_hdmi, true);
> +
>   	hdmi_val = SDVO_ENCODING_HDMI;
>   	if (!HAS_PCH_SPLIT(dev) && crtc->config->limited_color_range)
>   		hdmi_val |= HDMI_COLOR_RANGE_16_235;
> @@ -1142,6 +1160,8 @@ static void intel_disable_hdmi(struct intel_encoder *encoder)
>   	}
>
>   	intel_hdmi->set_infoframes(&encoder->base, false, NULL);
> +
> +	intel_dp_dual_mode_set_tmds_output(intel_hdmi, false);
>   }
>
>   static void g4x_disable_hdmi(struct intel_encoder *encoder)
>