Re: [PATCH 3/4] drm: nova: Add GETPARAM parameter to read the GPU chipset

[Alistair Popple]

On 2026-07-07 at 04:24 +1000, Danilo Krummrich <dakr@xxxxxxxxxx> wrote...
> On Mon Jul 6, 2026 at 7:35 PM CEST, Timur Tabi wrote:
> > On Mon, 2026-07-06 at 15:34 +1000, Alistair Popple wrote:
> >> @@ -38,6 +38,7 @@ pub(crate) fn get_param(
> >>  
> >>          let value = match getparam.param as u32 {
> >>              uapi::NOVA_GETPARAM_VRAM_BAR_SIZE => pdev.resource_len(1)?,
> >> +            uapi::NOVA_GETPARAM_GPU_CHIPSET => reg_data.api.chipset() as u64,
> >
> > Can we assign these IOCtl values to match Nouveau as much as possible?  I think it would make
> > everyone's life easier if we could use the same user-space tools/libraries for Nova that we do for
> > Nouveau.

I debated this, for the same reasons. However I came to the conclusion that it
wouldn't make a big difference - Nouveau only has a handful of GETPARAMs and
we already know we're going to need a lot more for Nova given the increased
scope of features it needs to support. The rest of the API also needs to be
sufficiently different so I didn't see any real practical advantage to keeping a
couple of parameters the same as tools will need updating anyway.

That said I don't know these tools well - did you have any particular examples
in mind?

 - Alistair

> I don't mind using the same numbers where it doesn't matter too much, but for
> this to work, it would also require us to retain layout compatibility with
> structures, semantics, etc., which I think we should not bother with at all.
> 
> Let's build a clean new uAPI, it will get messy over time by itself. :)