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

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

On Tue, 27 Aug 2024, Jani Nikula <jani.nikula@linux.intel.com> wrote:
> 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?

We can check for display 14.1 and we can check for IS_BATTLEMAGE().


>
>>
>> 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