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From:   Jani Nikula <jani.nikula@linux.intel.com>
To:     Matt Roper <matthew.d.roper@intel.com>
Cc:     "Surendrakumar Upadhyay\, TejaskumarX" 
        <tejaskumarx.surendrakumar.upadhyay@intel.com>,
        "Vivi\, Rodrigo" <rodrigo.vivi@intel.com>,
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        "Ausmus\, James" <james.ausmus@intel.com>,
        "Souza\, Jose" <jose.souza@intel.com>,
        "ville.syrjala\@linux.intel.com" <ville.syrjala@linux.intel.com>,
        "De Marchi\, Lucas" <lucas.demarchi@intel.com>,
        "Pandey\, Hariom" <hariom.pandey@intel.com>
Subject: Re: [PATCH 1/2] drm/i915/jsl: Split EHL/JSL platform info and PCI ids
In-Reply-To: <20200928172447.GA2157395@mdroper-desk1.amr.corp.intel.com>
Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo
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Date:   Mon, 28 Sep 2020 20:32:38 +0300
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On Mon, 28 Sep 2020, Matt Roper <matthew.d.roper@intel.com> wrote:
> Why are we adding IS_JASPERLAKE at all?  EHL/JSL are documented as the
> same graphics IP, but are paired with different PCHs in the final SoCs,
> which is what causes the minor differences in programming.  My
> understanding is that the voltage programming differences are ultimately
> due to that difference in PCH so we should just use HAS_PCH_MCC (EHL)
> and HAS_PCH_JSP (JSL) to distinguish which type of programming is needed
> rather than using a platform test.

Good point. If the difference is in the PCH, then of course the PCH
check should be used instead. Which avoids the problem altogether.

BR,
Jani.


-- 
Jani Nikula, Intel Open Source Graphics Center