Re: [Intel-gfx] [PATCH 3/4] drm/i915: Fix platform default aux ch for skl

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Fri, Feb 17, 2023 at 03:15:59PM +0530, Nautiyal, Ankit K wrote:
> 
> On 2/17/2023 4:43 AM, Ville Syrjala wrote:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >
> > SKL/derivatives have DDI E but no AUX E, so we need to pick
> > another aux ch as the platform default. DDI E is more or less
> > the other half of DDI A, so we pick AUX A.
> >
> > In all other cases we should have a corresponding aux ch for
> > each DDI.
> >
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > ---
> >   drivers/gpu/drm/i915/display/intel_dp_aux.c | 14 ++++++++++++--
> >   1 file changed, 12 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux.c b/drivers/gpu/drm/i915/display/intel_dp_aux.c
> > index 57eb3ff187fa..96967e21c94c 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp_aux.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp_aux.c
> > @@ -739,10 +739,20 @@ void intel_dp_aux_init(struct intel_dp *intel_dp)
> >   	cpu_latency_qos_add_request(&intel_dp->pm_qos, PM_QOS_DEFAULT_VALUE);
> >   }
> >   
> > +static enum aux_ch default_aux_ch(struct intel_encoder *encoder)
> > +{
> > +	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> > +
> > +	/* SKL has DDI E but no AUX E */
> > +	if (DISPLAY_VER(i915) == 9 && encoder->port == PORT_E)
> > +		return AUX_CH_A;
> > +
> 
> I guess we might need to fix intel_dp_aux_init also. Wont we have 
> dig_port->aux_ch and intel_dp->aux_ch pointing to different things?

There is no intel_dp->aux_ch.

> 
> For example for SKL and DDI E, intel_dp->aux.name will be derived from 
> dig_port->aux_ch i.e. AUX_CH_A but intel_dp->aux_ctl/data reg will still 
> point to DP_AUX_CH_CTL/DATA_E.
> 
> Am I missing something?

Everything is based on dig_port->aux_ch.

> 
> Regards,
> 
> Ankit
> 
> 
> > +	return (enum aux_ch)encoder->port;
> > +}
> > +
> >   enum aux_ch intel_dp_aux_ch(struct intel_encoder *encoder)
> >   {
> >   	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> > -	enum port port = encoder->port;
> >   	enum aux_ch aux_ch;
> >   
> >   	aux_ch = intel_bios_dp_aux_ch(encoder->devdata);
> > @@ -753,7 +763,7 @@ enum aux_ch intel_dp_aux_ch(struct intel_encoder *encoder)
> >   		return aux_ch;
> >   	}
> >   
> > -	aux_ch = (enum aux_ch)port;
> > +	aux_ch = default_aux_ch(encoder);
> >   
> >   	drm_dbg_kms(&i915->drm,
> >   		    "[ENCODER:%d:%s] using AUX %c (platform default)\n",

-- 
Ville Syrjälä
Intel