RE: [PATCH] drm/i915/display: BMG supports UHBR13.5

[Jani Nikula <jani.nikula@linux.intel.com>]

On Tue, 27 Aug 2024, "Murthy, Arun R" <arun.r.murthy@intel.com> wrote:
>> -----Original Message-----
>> From: Jani Nikula <jani.nikula@linux.intel.com>
>> Sent: Tuesday, August 27, 2024 1:11 PM
>> To: Murthy, Arun R <arun.r.murthy@intel.com>; intel-xe@lists.freedesktop.org;
>> intel-gfx@lists.freedesktop.org
>> Cc: Murthy, Arun R <arun.r.murthy@intel.com>
>> Subject: Re: [PATCH] drm/i915/display: BMG supports UHBR13.5
>> 
>> On Tue, 27 Aug 2024, Arun R Murthy <arun.r.murthy@intel.com> wrote:
>> > UHBR20 is not supported by battlemage and the maximum link rate
>> > supported is UHBR13.5
>> >
>> > HSD: 16023263677
>> > Signed-off-by: Arun R Murthy <arun.r.murthy@intel.com>
>> > ---
>> >  drivers/gpu/drm/i915/display/intel_dp.c | 13 +++++++++++--
>> >  1 file changed, 11 insertions(+), 2 deletions(-)
>> >
>> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
>> > b/drivers/gpu/drm/i915/display/intel_dp.c
>> > index 789c2f78826d..3232ec4b2889 100644
>> > --- a/drivers/gpu/drm/i915/display/intel_dp.c
>> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
>> > @@ -528,6 +528,10 @@ static void
>> >  intel_dp_set_source_rates(struct intel_dp *intel_dp)  {
>> >  	/* The values must be in increasing order */
>> > +	static const int bmg_rates[] = {
>> > +		162000, 216000, 243000, 270000, 324000, 432000, 540000,
>> 675000,
>> > +		810000,	1000000, 1350000,
>> > +	};
>> >  	static const int mtl_rates[] = {
>> >  		162000, 216000, 243000, 270000, 324000, 432000, 540000,
>> 675000,
>> >  		810000,	1000000, 2000000,
>> > @@ -558,8 +562,13 @@ intel_dp_set_source_rates(struct intel_dp *intel_dp)
>> >  		    intel_dp->source_rates || intel_dp->num_source_rates);
>> >
>> >  	if (DISPLAY_VER(dev_priv) >= 14) {
>> > -		source_rates = mtl_rates;
>> > -		size = ARRAY_SIZE(mtl_rates);
>> > +		if (IS_DGFX(dev_priv)) {
>> 
>> Why dgfx instead of bmg? Should be explained in commit message at the very
>> least.
>> 
> Likewise IS_DH2 / IS_MTL we don't have IS_BMG as its Display 14.1. One of the way to differentiate this is DISPLAY < 14 are integrated and this BMG is discrete and hence using IS_DGFX() for identifying BMG platform.

But isn't dgfx completely incidental here?

>
> Will add this in the commit message if not other comments and get Rb on this patch.
>
> Thanks and Regards,
> Arun R Murthy
> -------------------
>
>> BR,
>> Jani.
>> 
>> > +			source_rates = bmg_rates;
>> > +			size = ARRAY_SIZE(bmg_rates);
>> > +		} else {
>> > +			source_rates = mtl_rates;
>> > +			size = ARRAY_SIZE(mtl_rates);
>> > +		}
>> >  		max_rate = mtl_max_source_rate(intel_dp);
>> >  	} else if (DISPLAY_VER(dev_priv) >= 11) {
>> >  		source_rates = icl_rates;
>> 
>> --
>> Jani Nikula, Intel

-- 
Jani Nikula, Intel