[Intel-gfx] [PATCH] drm/i915/icl: Add pre_pll_enable hook for ICL and set DFLEXDPMLE in this hook

Mon Aug 13 22:12:03 UTC 2018

On Mon, Aug 13, 2018 at 12:38:00PM -0700, Souza, Jose wrote:
> On Tue, 2018-07-31 at 17:30 -0700, Manasi Navare wrote:
> > In case of Legacy DP connector on TypeC port (C, D, E or F), the
> 
> Legacy DP connector(DisplayPort Alternative Mode)

Ok will reword this as DisplayPort Alternative Mode

> 
> > flex IO DPMLE register is set to maximum number of lanes since
> > there is no muxing with other controllers in this case.
> 
> Okay there is no muxing but driver could choose to use few lanes do
> save power.
> 
> > While in case of the TypeC connector, it is set to the lane count
> > obained from DFLEXDPSP register.
> 
> obtained
> 
> > This needs to be programmed before enabling the shared PLLs hence
> > add a pre_pll_enable hook for ICL and add this programming in that
> > hook.
> > 
> > v3:
> > * Call intel_dp_max_common_lane_count that gets lane count
> > common between sink, source, fia
> > v2:
> > * Add pre pll enable hook and move dflexdpmle programming
> > to that hook (Animesh)
> > 
> > Cc: Jani Nikula <jani.nikula at linux.intel.com>
> > Cc: Animesh Manna <animesh.manna at intel.com>
> > Cc: Anusha Srivatsa <anusha.srivatsa at intel.com>
> > Cc: Paulo Zanoni <paulo.r.zanoni at intel.com>
> > Signed-off-by: Manasi Navare <manasi.d.navare at intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_ddi.c | 18 ++++++++++++++++++
> >  drivers/gpu/drm/i915/intel_dp.c  | 20 ++++++++++++++++++++
> >  drivers/gpu/drm/i915/intel_drv.h |  1 +
> >  3 files changed, 39 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_ddi.c
> > b/drivers/gpu/drm/i915/intel_ddi.c
> > index 0adc043..eb00ac4 100644
> > --- a/drivers/gpu/drm/i915/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/intel_ddi.c
> > @@ -3193,6 +3193,22 @@ static void bxt_ddi_pre_pll_enable(struct
> > intel_encoder *encoder,
> >  	bxt_ddi_phy_set_lane_optim_mask(encoder, mask);
> >  }
> >  
> > +static void icl_ddi_pre_pll_enable(struct intel_encoder *encoder,
> > +				   const struct intel_crtc_state
> > *pipe_config,
> > +				   const struct drm_connector_state
> > *conn_state)
> > +{
> > +	struct intel_dp *intel_dp = enc_to_intel_dp(&encoder->base);
> > +	struct intel_digital_port *intel_dig_port =
> > dp_to_dig_port(intel_dp);
> > +	struct drm_i915_private *dev_priv = to_i915(intel_dig_port-
> > >base.base.dev);
> > +	enum tc_port tc_port = intel_port_to_tc(dev_priv,
> > +						intel_dig_port-
> > >base.port);
> > +
> > +	if (tc_port == PORT_TC_NONE || intel_dig_port->tc_type ==
> > TC_PORT_TBT)
> > +		return;
> > +
> > +	intel_dp_set_fia_lane_count(intel_dp);
> > +}
> > +
> >  void intel_ddi_prepare_link_retrain(struct intel_dp *intel_dp)
> >  {
> >  	struct intel_digital_port *intel_dig_port =
> > dp_to_dig_port(intel_dp);
> > @@ -3709,6 +3725,8 @@ void intel_ddi_init(struct drm_i915_private
> > *dev_priv, enum port port)
> >  	intel_encoder->enable = intel_enable_ddi;
> >  	if (IS_GEN9_LP(dev_priv))
> >  		intel_encoder->pre_pll_enable = bxt_ddi_pre_pll_enable;
> > +	if (IS_ICELAKE(dev_priv))
> > +		intel_encoder->pre_pll_enable = icl_ddi_pre_pll_enable;
> 
> pre_pll_enable is set initialy in intel_crt_init() for most of the
> gens, maybe those 4 lines should be moved there but that can be done in
> another patch.

I think the crt_init() only has thecrt specific functions for DDI platforms
like hsw_crt_compute_config() hsw_enable_crt() etc, all the other ddi function pointers
are assigned in intel_ddi_init()

> 
> >  	intel_encoder->pre_enable = intel_ddi_pre_enable;
> >  	intel_encoder->disable = intel_disable_ddi;
> >  	intel_encoder->post_disable = intel_ddi_post_disable;
> > diff --git a/drivers/gpu/drm/i915/intel_dp.c
> > b/drivers/gpu/drm/i915/intel_dp.c
> > index 49a3149..6683cdc 100644
> > --- a/drivers/gpu/drm/i915/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > @@ -2127,6 +2127,26 @@ void intel_dp_set_link_params(struct intel_dp
> > *intel_dp,
> >  	intel_dp->link_mst = link_mst;
> >  }
> >  
> > +void intel_dp_set_fia_lane_count(struct intel_dp *intel_dp)
> > +{
> > +	struct drm_device *dev = intel_dp_to_dev(intel_dp);
> > +	struct drm_i915_private *dev_priv = to_i915(dev);
> > +	struct intel_digital_port *intel_dig_port =
> > dp_to_dig_port(intel_dp);
> > +	enum tc_port tc_port = intel_port_to_tc(dev_priv,
> > +						intel_dig_port-
> > >base.port);
> > +	u8 lane_count = intel_dp_max_common_lane_count(intel_dp);
> 
> intel_dp->max_link_lane_count could be used instead as it is set on
> hotplug and don't change over time.
> 
> But I guess this is also wrong, it should not enable the max lane
> count, it should enable the number of the lanes that the driver decides
> that is enough to the mode set to save power.

So I should be using crtc_state->lane_count here because thats what is the optimum
lane count computed in intel_dp_compute_config() for legacy DP connector.

In case of Type-C connector also, DFLEXDPSP only has the max lane count but the enable sequence
says:

"Dynamic - Program the number of lanes as per DFLEXDPSP.DPX4TXLATC*"
Also really the statement in the enable sequence "Program DFLEXDPMLE.DPMLETC* to maximum number of lanes allowed as determined by FIA and panel lane count." 
This makes it confusing as to whether we should set this to max or just the optimum required for the mode.

> 
> > +	u32 val;
> > +
> > +	/* In case of legacy/static DP over Type-C port there is no
> > muxing
> > +	 * with other controllers so this is set to max lane count.
> > +	 * In case of Type_C it is set to the DFLEXDPSP.DPX4TXLATC
> > value.
> > +	 */
> > +	val = I915_READ(PORT_TX_DFLEXDPMLE1);
> > +	val &= ~DFLEXDPMLE1_DPMLETC_MASK(tc_port);
> > +	val |= DFLEXDPMLE1_DPMLETC(tc_port, lane_count);
> 
> this macro is wrong, each bit set maps to a lane, so to enable all 4
> lanes it should 0xf for the first TC.
> 
> From spec:
> 
> For example, in DP Pin Assignment C, the register
> DFLEXDPSP1.DPX4TXLATC0 tells Display Driver that all the 4 TX Lane in
> PHY can be used. However, Display Driver may choose to use only x1,
> i.e. for ML0. Then Display Driver will program “0001b” to this
> register. For x2 and x4, Display Driver will program “0011b” and
> “1111b”, respectively.
>

Oh yes I realize now that there is no 1:1 mapping between lane count
and the value set in ML register
Lane count 1 - Value = 1
Lane count = 2, value = 3
Lane count = 4, Value = 0xf

I will change that logic.

Manasi

> 
> > +	I915_WRITE(PORT_TX_DFLEXDPMLE1, val);
> > +}
> > +
> >  static void intel_dp_prepare(struct intel_encoder *encoder,
> >  			     const struct intel_crtc_state
> > *pipe_config)
> >  {
> > diff --git a/drivers/gpu/drm/i915/intel_drv.h
> > b/drivers/gpu/drm/i915/intel_drv.h
> > index 1ad7c11..d98cdb9 100644
> > --- a/drivers/gpu/drm/i915/intel_drv.h
> > +++ b/drivers/gpu/drm/i915/intel_drv.h
> > @@ -1676,6 +1676,7 @@ bool intel_dp_init_connector(struct
> > intel_digital_port *intel_dig_port,
> >  void intel_dp_set_link_params(struct intel_dp *intel_dp,
> >  			      int link_rate, uint8_t lane_count,
> >  			      bool link_mst);
> > +void intel_dp_set_fia_lane_count(struct intel_dp *intel_dp);
> >  int intel_dp_get_link_train_fallback_values(struct intel_dp
> > *intel_dp,
> >  					    int link_rate, uint8_t
> > lane_count);
> >  void intel_dp_start_link_train(struct intel_dp *intel_dp);