Re: [Intel-gfx] [PATCH 04/13] drm/i915/tc: Check for DP-alt, legacy sinks before taking PHY ownership

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

On Fri, Sep 24, 2021 at 03:30:07AM +0300, Souza, Jose wrote:
> On Tue, 2021-09-21 at 03:23 +0300, Imre Deak wrote:
> > On ADL-P the PHY ready/complete flag is always set even in TBT-alt mode.
> > To avoid taking the PHY ownership and the following spurious "PHY sudden
> > disconnect" messages on this platform when connecting the PHY in TBT
> > mode, check if there is any DP-alt or legacy sink connected before
> > taking the ownership.
> > 
> > Cc: José Roberto de Souza <jose.souza@intel.com>
> > Signed-off-by: Imre Deak <imre.deak@intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_tc.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_tc.c b/drivers/gpu/drm/i915/display/intel_tc.c
> > index 0d3555437b0b1..1f76c11d70834 100644
> > --- a/drivers/gpu/drm/i915/display/intel_tc.c
> > +++ b/drivers/gpu/drm/i915/display/intel_tc.c
> > @@ -432,6 +432,13 @@ static void icl_tc_phy_connect(struct intel_digital_port *dig_port,
> >  		goto out_set_tbt_alt_mode;
> >  	}
> >  
> > +	if (!(tc_port_live_status_mask(dig_port) &
> > +	      (BIT(TC_PORT_DP_ALT) | BIT(TC_PORT_LEGACY)))) {
> > +		drm_dbg_kms(&i915->drm, "Port %s: nothing is connected\n",
> > +			    dig_port->tc_port_name);
> 
> Misleading log, it could have actual TBT connected and it would print
> nothing is connected.

Yes, missed that case. Will change that to print live_status_mask()
instead.

> Could you also add a comment in tc_phy_status_complete() about the TBT
> behavior on adl-p?

It means a different thing than what it means on previous platforms, can
add a note about this. 

> Fixing the above:
> Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
> 
> > +		goto out_set_tbt_alt_mode;
> > +	}
> > +
> >  	if (!tc_phy_take_ownership(dig_port, true) &&
> >  	    !drm_WARN_ON(&i915->drm, dig_port->tc_legacy_port))
> >  		goto out_set_tbt_alt_mode;
>