[Intel-gfx] [PATCH v2 2/7] drm/i915: Rename IS_GEN to GT_RANGE

[Lucas De Marchi]

On Wed, Nov 28, 2018 at 10:02:22AM +0200, Jani Nikula wrote:
> On Tue, 06 Nov 2018, Lucas De Marchi <lucas.demarchi at intel.com> wrote:
> > From: Rodrigo Vivi <rodrigo.vivi at intel.com>
> >
> > RANGE makes it longer, but clear. We are also going to add a check for
> > the display part, so make rename to GT.
> 
> I also still have my doubts about this patch I'm afraid. I've expressed
> the concern before, but here goes again.
> 
> How much is the split of gen to GT gen and display gen going to help us
> in the long run? The only current platform that would benefit from this
> is GLK. However, not all IS_GEMINILAKE() can be replaced with
> IS_DISPLAY_GEN() >= 10 or similar. We also have VLV/CHV display that is
> better represented by HAS_GMCH_DISPLAY() and AFAICT can't usefully be
> replaced by a display gen check.
> 
> My main fear is that the split adds a lot of confusion. (Where should I
> use GT gen, where should I use display gen, patches to change between
> one and the other. It's not 100% clear cut.)
> 
> Here too I wonder if we're better off adding more has_feature flags that
> describe what gt or display features a platform has.

It will never be a clear cut. Adding more flags make perfect sense when
there is such a feature to check for. Sometimes registers just change
location based on what is the display gen. Having the display gen serves
to group small differences together into a "single flag" if you will.
And today what we do is to actually check for gen rather than display
gen. Or a mix of platform names.

Lucas De Marchi