Re: [PATCH 09/23] drm/i915: Factor out common parts from TypeC port handling functions

[Imre Deak <imre.deak@intel.com>]

On Tue, Jun 18, 2019 at 07:33:13PM +0300, Ville Syrjälä wrote:
> On Tue, Jun 04, 2019 at 05:58:12PM +0300, Imre Deak wrote:
> > Factor out helpers reading/parsing the TypeC specific registers, making
> > current users of them clearer and letting us use them later.
> > 
> > While at it also:
> > - Simplify icl_tc_phy_connect() with an early return in legacy mode.
> > - Simplify the live status check using one bitmask for all HPD bits.
> > - Remove a micro-optimisation of the repeated safe-mode clearing.
> > - Make sure we fix the legacy port flag in all cases.
> > 
> > Except for the last two, no functional changes.
> > 
> > Cc: José Roberto de Souza <jose.souza@intel.com>
> > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
> > Signed-off-by: Imre Deak <imre.deak@intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_ddi.c |   5 +-
> >  drivers/gpu/drm/i915/intel_tc.c  | 166 +++++++++++++++++++------------
> >  drivers/gpu/drm/i915/intel_tc.h  |   1 +
> >  3 files changed, 103 insertions(+), 69 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> > index 8f223d48d562..d236839bee19 100644
> > --- a/drivers/gpu/drm/i915/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/intel_ddi.c
> > @@ -2983,7 +2983,6 @@ static void icl_program_mg_dp_mode(struct intel_digital_port *intel_dig_port)
> >  {
> >  	struct drm_i915_private *dev_priv = to_i915(intel_dig_port->base.base.dev);
> >  	enum port port = intel_dig_port->base.port;
> > -	enum tc_port tc_port = intel_port_to_tc(dev_priv, port);
> >  	u32 ln0, ln1, lane_info;
> >  
> >  	if (intel_dig_port->tc_mode == TC_PORT_TBT_ALT)
> > @@ -2997,9 +2996,7 @@ static void icl_program_mg_dp_mode(struct intel_digital_port *intel_dig_port)
> >  		ln0 &= ~(MG_DP_MODE_CFG_DP_X1_MODE | MG_DP_MODE_CFG_DP_X2_MODE);
> >  		ln1 &= ~(MG_DP_MODE_CFG_DP_X1_MODE | MG_DP_MODE_CFG_DP_X2_MODE);
> >  
> > -		lane_info = (I915_READ(PORT_TX_DFLEXDPSP) &
> > -			     DP_LANE_ASSIGNMENT_MASK(tc_port)) >>
> > -			    DP_LANE_ASSIGNMENT_SHIFT(tc_port);
> > +		lane_info = intel_tc_port_get_lane_info(intel_dig_port);
> >  
> >  		switch (lane_info) {
> >  		case 0x1:
> > diff --git a/drivers/gpu/drm/i915/intel_tc.c b/drivers/gpu/drm/i915/intel_tc.c
> > index 07488235b67a..3fdcfa2bbaee 100644
> > --- a/drivers/gpu/drm/i915/intel_tc.c
> > +++ b/drivers/gpu/drm/i915/intel_tc.c
> > @@ -43,10 +43,19 @@ static const char *tc_port_mode_name(enum tc_port_mode mode)
> >  	return names[mode];
> >  }
> >  
> > -int intel_tc_port_fia_max_lane_count(struct intel_digital_port *dig_port)
> > +u32 intel_tc_port_get_lane_info(struct intel_digital_port *dig_port)
> 
> get_lane_mask() or something?

Ok.

> 
> >  {
> >  	struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
> >  	enum tc_port tc_port = intel_port_to_tc(dev_priv, dig_port->base.port);
> > +	u32 lane_info = I915_READ(PORT_TX_DFLEXDPSP);
> > +
> > +	return (lane_info & DP_LANE_ASSIGNMENT_MASK(tc_port)) >>
> > +	       DP_LANE_ASSIGNMENT_SHIFT(tc_port);
> > +}
> > +
> > +int intel_tc_port_fia_max_lane_count(struct intel_digital_port *dig_port)
> > +{
> > +	struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
> >  	intel_wakeref_t wakeref;
> >  	u32 lane_info;
> >  
> > @@ -55,9 +64,7 @@ int intel_tc_port_fia_max_lane_count(struct intel_digital_port *dig_port)
> >  
> >  	lane_info = 0;
> >  	with_intel_display_power(dev_priv, POWER_DOMAIN_DISPLAY_CORE, wakeref)
> > -		lane_info = (I915_READ(PORT_TX_DFLEXDPSP) &
> > -			     DP_LANE_ASSIGNMENT_MASK(tc_port)) >>
> > -				DP_LANE_ASSIGNMENT_SHIFT(tc_port);
> > +		lane_info = intel_tc_port_get_lane_info(dig_port);
> >  
> >  	switch (lane_info) {
> >  	default:
> > @@ -75,6 +82,69 @@ int intel_tc_port_fia_max_lane_count(struct intel_digital_port *dig_port)
> >  	}
> >  }
> >  
> > +static void tc_port_fixup_legacy_flag(struct intel_digital_port *dig_port,
> > +				      u32 live_status_mask)
> > +{
> > +	struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
> > +	enum tc_port tc_port = intel_port_to_tc(dev_priv, dig_port->base.port);
> > +	u32 valid_hpd_mask = dig_port->tc_legacy_port ? BIT(TC_PORT_LEGACY) :
> > +							~BIT(TC_PORT_LEGACY);
> > +
> > +	if (!(live_status_mask & ~valid_hpd_mask))
> > +		return;
> 
> A bit too many nots for me to follow. I guess what it's doing is
> checking if any of the other bits are set, and if so it assumes the
> mode was misdeclared in vbt? 

Yes.

> 
> Actually, won't this end up ping-ponging back and forth if the
> hw really reports both legacy and non-legacy bits as set?

If you mean multiple HPD bits being set by HW, we won't call this
function to fix up the flag.

> 
> > +
> > +	/* If live status mismatches the VBT flag, trust the live status. */
> > +	DRM_ERROR("Port %s: live status %08x mismatches the legacy port flag, fix flag\n",
> > +		  tc_port_name(dev_priv, tc_port), live_status_mask);
> > +
> > +	dig_port->tc_legacy_port = !dig_port->tc_legacy_port;
> > +}
> > +
> 
> -- 
> Ville Syrjälä
> Intel
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