[Intel-gfx] [PATCH v2 7/8] drm/i915/tc: Catch TC users accessing FIA registers without enable aux

[Imre Deak]

On Tue, Apr 07, 2020 at 07:04:55PM +0300, Imre Deak wrote:
> On Mon, Apr 06, 2020 at 06:11:56PM -0700, José Roberto de Souza wrote:
> > As described in "drm/i915/tc/icl: Implement TC cold sequences" users
> > of TC functions should held aux power well during access to avoid
> > read garbage due HW in TC cold state.
> > 
> > Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_tc.c | 22 ++++++++++++++++++++--
> >  1 file changed, 20 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_tc.c b/drivers/gpu/drm/i915/display/intel_tc.c
> > index 83861653768d..e473bb4a9b0b 100644
> > --- a/drivers/gpu/drm/i915/display/intel_tc.c
> > +++ b/drivers/gpu/drm/i915/display/intel_tc.c
> > @@ -95,6 +95,20 @@ tc_cold_unblock(struct intel_digital_port *dig_port, intel_wakeref_t wakeref)
> >  	intel_display_power_put_async(i915, domain, wakeref);
> >  }
> >  
> > +static void
> > +is_tc_cold_blocked(struct intel_digital_port *dig_port)
> 
> assert_tc_cold_blocked()?
> 
> Reviewed-by: Imre Deak <imre.deak at intel.com>
> 
> > +{
> > +	struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
> > +	bool enabled;
> > +
> > +	if (INTEL_GEN(i915) == 11 && !dig_port->tc_legacy_port)
> > +		return;
> > +
> > +	enabled = intel_display_power_is_enabled(i915,
> > +						 tc_cold_get_power_domain(dig_port));
> > +	drm_WARN_ON(&i915->drm, !enabled);
> > +}
> > +
> >  u32 intel_tc_port_get_lane_mask(struct intel_digital_port *dig_port)
> >  {
> >  	struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
> > @@ -104,7 +118,7 @@ u32 intel_tc_port_get_lane_mask(struct intel_digital_port *dig_port)
> >  	lane_mask = intel_uncore_read(uncore,
> >  				      PORT_TX_DFLEXDPSP(dig_port->tc_phy_fia));
> >  
> > -	drm_WARN_ON(&i915->drm, lane_mask == 0xffffffff);

You could also keep the checks like the above one, since reading all
0xff is still bogus.

> > +	is_tc_cold_blocked(dig_port);
> >  
> >  	lane_mask &= DP_LANE_ASSIGNMENT_MASK(dig_port->tc_phy_fia_idx);
> >  	return lane_mask >> DP_LANE_ASSIGNMENT_SHIFT(dig_port->tc_phy_fia_idx);
> > @@ -119,7 +133,7 @@ u32 intel_tc_port_get_pin_assignment_mask(struct intel_digital_port *dig_port)
> >  	pin_mask = intel_uncore_read(uncore,
> >  				     PORT_TX_DFLEXPA1(dig_port->tc_phy_fia));
> >  
> > -	drm_WARN_ON(&i915->drm, pin_mask == 0xffffffff);
> > +	is_tc_cold_blocked(dig_port);
> >  
> >  	return (pin_mask & DP_PIN_ASSIGNMENT_MASK(dig_port->tc_phy_fia_idx)) >>
> >  	       DP_PIN_ASSIGNMENT_SHIFT(dig_port->tc_phy_fia_idx);
> > @@ -134,6 +148,8 @@ int intel_tc_port_fia_max_lane_count(struct intel_digital_port *dig_port)
> >  	if (dig_port->tc_mode != TC_PORT_DP_ALT)
> >  		return 4;
> >  
> > +	is_tc_cold_blocked(dig_port);
> > +
> >  	lane_mask = 0;
> >  	with_intel_display_power(i915, POWER_DOMAIN_DISPLAY_CORE, wakeref)
> >  		lane_mask = intel_tc_port_get_lane_mask(dig_port);
> > @@ -166,6 +182,8 @@ void intel_tc_port_set_fia_lane_count(struct intel_digital_port *dig_port,
> >  	drm_WARN_ON(&i915->drm,
> >  		    lane_reversal && dig_port->tc_mode != TC_PORT_LEGACY);
> >  
> > +	is_tc_cold_blocked(dig_port);
> > +
> >  	val = intel_uncore_read(uncore,
> >  				PORT_TX_DFLEXDPMLE1(dig_port->tc_phy_fia));
> >  	val &= ~DFLEXDPMLE1_DPMLETC_MASK(dig_port->tc_phy_fia_idx);
> > -- 
> > 2.26.0
> > 
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