[Intel-gfx] [PATCH] drm/i915/display/dp: Remove support for UHBR13.5

[Murthy, Arun R]

> -----Original Message-----
> From: Nikula, Jani <jani.nikula at intel.com>
> Sent: Wednesday, June 21, 2023 2:27 PM
> To: Murthy, Arun R <arun.r.murthy at intel.com>; intel-
> gfx at lists.freedesktop.org
> Cc: Deak, Imre <imre.deak at intel.com>; Kahola, Mika
> <mika.kahola at intel.com>; Murthy, Arun R <arun.r.murthy at intel.com>
> Subject: Re: [PATCH] drm/i915/display/dp: Remove support for UHBR13.5
> 
> On Tue, 20 Jun 2023, Arun R Murthy <arun.r.murthy at intel.com> wrote:
> > As per the DP2.1 Spec support for UHBR13.5 is optional. Hence removing
> > the support for UHBR13.5
> 
> That's just not a proper rationale. Please explain.
> 
Programming for UHBR10 and UHBR20 is similar compared to UHBR13.5
As of now we have validated 10Gbps and 20Gbps. The spec also points out when 20Gbps is supported 13.5Gbps is optional so we have not validated/implemented the UHBR13.5
Now we have the DP2.1 compatible panel is market, expecting users can come up with UHBR13.5 not working. Hence removing the support for 13.5Gbps for now.
Maybe once we have support for UHBR13.5 in the driver we can enable this.

Thanks and Regards,
Arun R Murthy
--------------------
> BR,
> Jani.
> 
> 
> > UHBR10 can be used for 6k panels.
> >
> > Signed-off-by: Arun R Murthy <arun.r.murthy at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_dp.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> > b/drivers/gpu/drm/i915/display/intel_dp.c
> > index 9f40da20e88d..54ddc953e5bc 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > @@ -465,7 +465,7 @@ intel_dp_set_source_rates(struct intel_dp
> *intel_dp)
> >  	};
> >  	static const int icl_rates[] = {
> >  		162000, 216000, 270000, 324000, 432000, 540000, 648000,
> 810000,
> > -		1000000, 1350000,
> > +		1000000,
> >  	};
> >  	static const int bxt_rates[] = {
> >  		162000, 216000, 243000, 270000, 324000, 432000, 540000
> 
> --
> Jani Nikula, Intel Open Source Graphics Center