Re: [PATCH RFC 10/13] drm/msm: initialize LPAC ring

[Anna Maniscalco]

On 7/6/26 10:44 AM, Konrad Dybcio wrote:
> On 7/5/26 9:13 PM, Anna Maniscalco wrote:
> > Program all the register needed to start up LPAC and send initialization
> > sequence.
> >
> > Additionally, now that the LPAC ring is live, make the code aware of it.
> >
> > Signed-off-by: Anna Maniscalco <anna.maniscalco2000@xxxxxxxxx>
> > ---
> I believe some/all of these writes need to be guarded by if (has_lpac),
> as many GPUs lack these registers and there may be side effects on
> others

That's correct yeah. I'm not sure what has_lpac should be though.

Something we add to catalog? Or checking if it is a gen that has LPAC?

> [...]
>
> >   		a6xx_gpu->shadow = msm_gem_kernel_new(gpu->dev,
> > -						      sizeof(u32) * gpu->nr_rings,
> > +						      sizeof(u32) * (gpu->nr_rings + !!gpu->lpac_rb),
> Should we rename nr_rings to something like nr_XXX_rings
> where XXX is some uarch-generic (i.e. not SQE because we also
> support pre-a6xx) name for the main number cruncher?
Qualcom calls it GC so nr_gc_rings perhaps?
> Konrad


Best regards,
--
Anna Maniscalco <anna.maniscalco2000@xxxxxxxxx>