Re: [CI 1/2] drm/i915/icl: Add allowed DP rates for Icelake

[Manasi Navare <manasi.d.navare@intel.com>]

On Wed, Jun 13, 2018 at 12:42:20PM -0700, Paulo Zanoni wrote:
> Em Ter, 2018-06-12 às 11:37 -0700, Manasi Navare escreveu:
> > On Tue, Jun 12, 2018 at 03:15:53PM +0300, Ville Syrjälä wrote:
> > > On Mon, Jun 11, 2018 at 03:26:54PM -0700, Paulo Zanoni wrote:
> > > > From: Manasi Navare <manasi.d.navare@intel.com>
> > > > 
> > > > For ICL, on Combo PHY the allowed max rates are:
> > > >  - HBR3 8.1 eDP (DDIA)
> > > >  - HBR2 5.4 DisplayPort (DDIB)
> > > > and for MG PHY/TC DDI Ports allowed DP rates are:
> > > >  - HBR3 8.1 DisplayPort (DP alternate mode, DP over TBT,
> > > >  - DP on legacy connector - DDIC/D/E/F)
> > > > 
> > > > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > > > Cc: Jani Nikula <jani.nikula@linux.intel.com>
> > > > Reviewed-by: James Ausmus <james.ausmus@intel.com>
> > > > Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
> > > > Signed-off-by: James Ausmus <james.ausmus@intel.com>
> > > > [Paulo: bikeshed to keep future platforms on "else".]
> > > > Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
> > > > ---
> > > >  drivers/gpu/drm/i915/intel_dp.c | 21 +++++++++++++++++++--
> > > >  1 file changed, 19 insertions(+), 2 deletions(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/i915/intel_dp.c
> > > > b/drivers/gpu/drm/i915/intel_dp.c
> > > > index 37b9f62aeb6e..8371159cc192 100644
> > > > --- a/drivers/gpu/drm/i915/intel_dp.c
> > > > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > > > @@ -256,6 +256,20 @@ static int cnl_max_source_rate(struct
> > > > intel_dp *intel_dp)
> > > >  	return 810000;
> > > >  }
> > > >  
> > > > +static int icl_max_source_rate(struct intel_dp *intel_dp)
> > > > +{
> > > > +	struct intel_digital_port *dig_port =
> > > > dp_to_dig_port(intel_dp);
> > > > +	enum port port = dig_port->base.port;
> > > > +
> > > > +	/* On Combo PHY port A max speed is HBR3 for all Vccio
> > > > voltages
> > > > +	 * and on Combo PHY Port B the maximum supported is
> > > > HBR2.
> > > > +	 */
> > > 
> > > And what about the other ports? If port B is the only
> > > exception why are we even discussing port A specifically
> > > here?
> > 
> > All the MG PHY ports (C/D/E/F)  support a max of HBR3 that is 810000
> > but for
> > Combo PHY ports which is Port A or B, HBR3 only supported for Port A
> > but for Port B it is max of HBR2 which is 540000 hence the comment
> > for Combo PHY
> > ports and if port B then just return HBR2
> 
> I think Ville's point was that having a comment that only discusses
> ports A and B on code that handles all ports gives the impression that
> perhaps the code is "forgetting" to consider the other ports, or
> something like that. Which makes sense to me.
> 
> Perhaps to address this issue we could either reword the comment to
> include C-F or simply just remove it, since the commit message should
> be enough and the comment only says what the code says.
>

Yes I agree. Lets remove the comment in the code since the commit message
covers that part.
Should I send a new revision for this with comment removed?

Manasi 

> > 
> > Manasi
> > 
> > > 
> > > > +	if (port == PORT_B)
> > > > +		return 540000;
> > > > +
> > > > +	return 810000;
> > > > +}
> > > > +
> > > >  static void
> > > >  intel_dp_set_source_rates(struct intel_dp *intel_dp)
> > > >  {
> > > > @@ -285,10 +299,13 @@ intel_dp_set_source_rates(struct intel_dp
> > > > *intel_dp)
> > > >  	/* This should only be done once */
> > > >  	WARN_ON(intel_dp->source_rates || intel_dp-
> > > > >num_source_rates);
> > > >  
> > > > -	if (IS_CANNONLAKE(dev_priv)) {
> > > > +	if (INTEL_GEN(dev_priv) >= 10) {
> > > >  		source_rates = cnl_rates;
> > > >  		size = ARRAY_SIZE(cnl_rates);
> > > > -		max_rate = cnl_max_source_rate(intel_dp);
> > > > +		if (INTEL_GEN(dev_priv) == 10)
> > > > +			max_rate =
> > > > cnl_max_source_rate(intel_dp);
> > > > +		else
> > > > +			max_rate =
> > > > icl_max_source_rate(intel_dp);
> > > >  	} else if (IS_GEN9_LP(dev_priv)) {
> > > >  		source_rates = bxt_rates;
> > > >  		size = ARRAY_SIZE(bxt_rates);
> > > > -- 
> > > > 2.14.4
> > > > 
> > > > _______________________________________________
> > > > Intel-gfx mailing list
> > > > Intel-gfx@lists.freedesktop.org
> > > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > > 
> > > -- 
> > > Ville Syrjälä
> > > Intel
> > > _______________________________________________
> > > Intel-gfx mailing list
> > > Intel-gfx@lists.freedesktop.org
> > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
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