[PATCH 1/5] drm/i915: don't include CML PCI IDs in CFL

[Jani Nikula]

On Fri, 10 May 2024, Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:
> On Fri, May 10, 2024 at 01:24:12PM +0300, Jani Nikula wrote:
>> On Wed, 08 May 2024, Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:
>> > On Wed, May 08, 2024 at 02:45:10PM +0300, Jani Nikula wrote:
>> >> On Wed, 08 May 2024, Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:
>> >> > On Tue, May 07, 2024 at 09:47:16AM -0400, Rodrigo Vivi wrote:
>> >> >> On Tue, May 07, 2024 at 03:56:48PM +0300, Jani Nikula wrote:
>> >> >> > It's confusing for INTEL_CFL_IDS() to include all CML PCI IDs. Even if
>> >> >> > we treat them the same in a lot of places, CML is a platform of its own,
>> >> >> > and the lists of PCI IDs should not conflate them.
>> 
>> [snip]
>> 
>> >> >> Why only CML and not AML and WHL as well?
>> >> >
>> >> > Why do we even have CML as a separate platform? The only difference 
>> >> > I can see is is that we do allow_read_ctx_timestamp() for CML but
>> >> > not for CFL. Does that even make sense?
>> >> 
>> >> git blame tells me:
>> >> 
>> >> 5f4ae2704d59 ("drm/i915: Identify Cometlake platform")
>> >> dbc7e72897a4 ("drm/i915/gt: Make the CTX_TIMESTAMP readable on !rcs")
>> >
>> > Right. That explains why we need it on CML+. But is there some reason
>> > we  can't just do it on CFL as well, even if not strictly necessary?
>> > I would assume that setting FORCE_TO_NONPRIV on an already
>> > non-privileged register should be totally fine.
>> 
>> I have absolutely no idea.
>> 
>> I'm somewhat thinking "CML being a separate platform" is a separate
>> problem from "CFL PCI ID macros including CML".
>> 
>> I'm starting to think the PCI ID macros should be grouped by "does the
>> platform have a name of its own",
>
> That and/or "does bspec have a separate 'Confgurations <platform>' page?"
>
>> not by how those macros are actually
>> used by the driver. Keeping them separate at the PCI ID macro level just
>> reduces the pain in maintaining the PCI IDs, and lets us wiggle stuff
>> around in the driver how we see fit.
>
> Aye.
>
>> 
>> And that spins back to Rodrigo's question, "Why only CML and not AML and
>> WHL as well?". Yeah, indeed.
>> 
>> If we decide to stop treating CML as a separate platform in the
>> *driver*, that's another matter.
>
> Sure. Seeing it just got me wondering...

I sent a new series with just the PCI ID macro cleanups [1]. I meant to
Cc: you and Rodrigo, but forgot. :(

BR,
Jani.

[1] https://patchwork.freedesktop.org/series/133444/



-- 
Jani Nikula, Intel