Nouveau - Nov 2025 - [PATCH 3/6] gpu: nova-core: Blackwell: basic GPU identification

On Wed, 19 Nov 2025 at 12:46, Alexandre Courbot <acourbot at nvidia.com>
wrote:
>
> On Wed Nov 19, 2025 at 10:46 AM JST, John Hubbard wrote:
> > On 11/6/25 2:24 PM, John Hubbard wrote:
> >> On 11/6/25 6:44 AM, Timur Tabi wrote:
> >>> On Wed, 2025-11-05 at 19:54 -0800, John Hubbard wrote:
> >>>>       let hal = match chipset {
> >>>> -        GA102 | GA103 | GA104 | GA106 | GA107 | GH100 |
AD102 | AD103 | AD104 | AD106 | AD107
> >>>> => {
> >>>> +        GA102 | GA103 | GA104 | GA106 | GA107 | GH100 |
AD102 | AD103 | AD104 | AD106 | AD107
> >>>> +        | GB100 | GB102 | GB202 | GB203 | GB205 | GB206 |
GB207 => {
> >>>>               KBox::new(ga102::Ga102::<E>::new(),
GFP_KERNEL)? as KBox<dyn FalconHal<E>>
> >>>>           }
> >>>
> >>> Maybe combine patches 2 and 3?  Also, maybe this should be a
range check, instead of listing
> >>> every since version?  It seems like everything past GA100 uses
the GA102 HAL.
> >>>
> >>
> >> Sure, I can combine the patches.
> >>
> >> I'm not sure why I've been wary of using ranges for these
arch's.
> >> I'll try it out.
> >
> > Now I know. :)  Unlike C, Rust does *not* like it when we try to
> > treat enums as integers. Casting or other (messier) approaches are
> > required, and in no case is the end result a more readable on-screen
> > experience. At least not so far.
> >
> > It is possible to mix in Architecture (Turing, Ampere, etc) checks,
> > but I'm not sure that is worth the additional clutter.
> >
> > Maybe let's just do the long lists of chipsets for now...?
>
> Yeah, I've hit this issue as well. The compiler might remove that
> limitation in the future, or maybe we can craft a `chipset_range!()`
> macro that hides the messy casting, but this exhaustive listing also has
> the benefit of forcing us to consider every critical site whenever we
> support a new chipset so I'm actually not too bothered by it.
I wrote some macros in my nova-core-experiments, had
chipset_before/after/range I think

Dave.

On 11/18/25 7:15 PM, Dave Airlie wrote:
> On Wed, 19 Nov 2025 at 12:46, Alexandre Courbot <acourbot at
nvidia.com> wrote:
...
>>> Maybe let's just do the long lists of chipsets for now...?
>>
>> Yeah, I've hit this issue as well. The compiler might remove that
>> limitation in the future, or maybe we can craft a `chipset_range!()`
>> macro that hides the messy casting, but this exhaustive listing also
has
>> the benefit of forcing us to consider every critical site whenever we
>> support a new chipset so I'm actually not too bothered by it.
> 
> I wrote some macros in my nova-core-experiments, had
> chipset_before/after/range I think
> 
aha, I was afraid someone was going to say "macros" out loud, at some
point. And now you've gone and done it. :)

Well, I think we probably want:

a) The ability to clearly specify a chipset range, and

b) For extra credit, maybe: also be able to specify entire GPU
architectures, and architecture ranges.

...again, without too much extraneous noise at the call sites: the goal is
to read it easily:

     GA102..=GA104 | Architecture::Blackwell


for example. Macros are going to require that to be less clean, but
let me poke around and see.

thanks,
-- 
John Hubbard