[Intel-gfx] [PATCH v2 3/4] drm/i915: Enable/disable TMDS output buffers in DP++ adaptor as needed

Ville Syrjälä ville.syrjala at linux.intel.com
Thu Mar 31 20:39:28 UTC 2016


On Thu, Mar 31, 2016 at 07:26:25PM +0000, Zanoni, Paulo R wrote:
> Em Qui, 2016-02-25 às 14:51 +0200, ville.syrjala at linux.intel.com
> escreveu:
> > From: Ville Syrjälä <ville.syrjala at 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
> > 
> > Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_ddi.c  | 12 ++++++++++++
> >  drivers/gpu/drm/i915/intel_drv.h  |  2 ++
> >  drivers/gpu/drm/i915/intel_hdmi.c | 31
> > +++++++++++++++++++++++++++++--
> >  3 files changed, 43 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_ddi.c
> > b/drivers/gpu/drm/i915/intel_ddi.c
> > index 21a9b83f3bfc..458c41788b80 100644
> > --- a/drivers/gpu/drm/i915/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/intel_ddi.c
> > @@ -2301,6 +2301,12 @@ 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) {
> > +		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) {
> > @@ -2367,6 +2373,12 @@ 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) {
> > +		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 944eacbfb6a9..2e4fa4337c59 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -706,6 +706,7 @@ struct intel_hdmi {
> >  	int ddc_bus;
> >  	struct {
> >  		int max_tmds_clock;
> > +		bool tmds_output_control;
> >  	} dp_dual_mode;
> >  	bool limited_color_range;
> >  	bool color_range_auto;
> > @@ -1355,6 +1356,7 @@ 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 1e8cfdb18dc7..4b528a669f8e 100644
> > --- a/drivers/gpu/drm/i915/intel_hdmi.c
> > +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> > @@ -837,6 +837,20 @@ 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)
> > +{
> > +	if (hdmi->dp_dual_mode.tmds_output_control) {
> 
> Or you could just do an early return here and save an indentation level
> :)

Indeed. I had the code inlined originally so the extra indentation
made sense, and the I just copypasted it to this separate function,
and in my haste forgot to flatten it.

> 
> > +		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);
> > +
> > +		DRM_DEBUG_KMS("%s DP dual mode adaptor TMDS
> > output\n",
> > +			      enable ? "Enabling" : "Disabling");
> > +
> > +		drm_dp_dual_mode_set_tmds_output(adapter, enable);
> > +	}
> > +}
> > +
> >  static void intel_hdmi_prepare(struct intel_encoder *encoder)
> >  {
> >  	struct drm_device *dev = encoder->base.dev;
> > @@ -846,6 +860,8 @@ 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;
> > @@ -1144,6 +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)
> > @@ -1369,6 +1387,7 @@ intel_hdmi_unset_edid(struct drm_connector
> > *connector)
> >  	intel_hdmi->rgb_quant_range_selectable = false;
> >  
> >  	intel_hdmi->dp_dual_mode.max_tmds_clock = 0;
> > +	intel_hdmi->dp_dual_mode.tmds_output_control = false;
> >  
> >  	kfree(to_intel_connector(connector)->detect_edid);
> >  	to_intel_connector(connector)->detect_edid = NULL;
> > @@ -1392,15 +1411,23 @@ intel_hdmi_dp_dual_mode_detect(struct
> > drm_connector *connector)
> >  	 */
> >  	if (type == DRM_DP_DUAL_MODE_TYPE2_DVI ||
> >  	    type == DRM_DP_DUAL_MODE_TYPE2_HDMI) {
> > +		bool tmds_enabled;
> > +
> >  		hdmi->dp_dual_mode.max_tmds_clock =
> >  			drm_dp_dual_mode_max_tmds_clock(adapter);
> > +
> > +		hdmi->dp_dual_mode.tmds_output_control =
> > +			drm_dp_dual_mode_get_tmds_output(adapter,
> > &tmds_enabled) == 0 &&
> > +			drm_dp_dual_mode_set_tmds_output(adapter,
> > tmds_enabled) == 0;
> >  	} else {
> >  		hdmi->dp_dual_mode.max_tmds_clock = 165000;
> > +		hdmi->dp_dual_mode.tmds_output_control = false;
> 
> While type 1 adaptors are not required to implement the register, what
> if they do?

I suppose we could just always do the i2c write and if the adaptor
supports it everything is peachy, and if it doesn't, well, then I
suppose the write just goes to /dev/null and nothing should happen.

> We could potentially keep TMDS disabled forever.

That would be an entirely broken adaptor since it would not work at all
with source devices that are not dual mode aware.

> Maybe my
> suggestions on p1 would help a little bit here?
> 
> Anyway, what we have here is already better than the previous state, so
> if no rebase is required:
> 
> Reviewed-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> 
> >  	}
> >  
> > -	DRM_DEBUG_KMS("DP dual mode adaptor (%s) detected (max TMDS
> > clock: %d kHz)\n",
> > +	DRM_DEBUG_KMS("DP dual mode adaptor (%s) detected (max TMDS
> > clock: %d kHz, TMDS OE# control: %s)\n",
> >  		      drm_dp_get_dual_mode_type_name(type),
> > -		      hdmi->dp_dual_mode.max_tmds_clock);
> > +		      hdmi->dp_dual_mode.max_tmds_clock,
> > +		      yesno(hdmi-
> > >dp_dual_mode.tmds_output_control));
> >  }
> >  
> >  static bool

-- 
Ville Syrjälä
Intel OTC


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