[Intel-gfx] [PATCH] drm/i915: remove indirection in the PCI ID macros

[Chris Wilson]

On Tue, Feb 03, 2015 at 03:05:05PM +0200, Jani Nikula wrote:
> On Tue, 03 Feb 2015, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> > On Tue, Feb 03, 2015 at 02:34:05PM +0200, Jani Nikula wrote:
> >> Spell all the PCI IDs out to be able to quickly grep for the IDs. No
> >> functional changes.
> >
> > On the other hand this is a loss of contextual information in the header
> > file.
> 
> I assume the GT count is what you're referring to. I contemplated that,
> and decided that I, personally, really value the file as the canonical
> place to look at all the supported PCI IDs above all.

Exactly, which is why keeping the extra contextual information we have
is useful and why we want to keep changes here concise.
 
> Also, I'm pretty sure there's nothing in the specs that make guarantees
> about digits in PCI IDs mapping to GT count. My impression is that it's
> just an inference on our part, valid for the set of PCI IDs currently in
> the file. But this isn't that important.

It has been deliberate since SNB, since the introduction of varying GT
parts, much to the annoyance of people who rightly state that is not
what PCI ID was meant for. It is also how we detect which GT the chipset
is.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre