Re: [PATCH 09/13] drm/msm: Add per-context perfcntr state

[Rob Clark]

On Tue, Apr 21, 2026 at 8:37 PM Dmitry Baryshkov
<dmitry.baryshkov@xxxxxxxxxxxxxxxx> wrote:
>
> On Mon, Apr 20, 2026 at 03:25:31PM -0700, Rob Clark wrote:
> > The upcoming PERFCNTR_CONFIG ioctl will allow for both global counter
> > collection, and per-context counter reservation for local (ie. within
> > a single GEM_SUBMIT ioctl) counter collection.
> >
> > Any number of contexts can reserve the same counters, but we will need
> > to ensure that counters reserved for local counter collection do not
> > conflict with counters used for global counter collection.
> >
> > So add tracking for per-context local counter reservations.
> >
> > Signed-off-by: Rob Clark <robin.clark@xxxxxxxxxxxxxxxx>
>
> >
> > +struct msm_perfcntr_context_state {
> > +     /**
> > +      * @reserved_counters:
> > +      *
> > +      * The number of reserved counters indexed by perfcntr group.
> > +      */
> > +     unsigned reserved_counters[];
> > +};
>
> Fails here (Debian, trixie, gcc 14.2) with:
>
> In file included from drivers/gpu/drm/msm/generated/a6xx_perfcntrs.json.c:7:
> ./drivers/gpu/drm/msm/msm_perfcntr.h:130:18: error: flexible array member in a struct with no named members
>   130 |         unsigned reserved_counters[];
>       |                  ^~~~~~~~~~~~~~~~~

ugg... gcc 15.2.1 seems ok with this.  I guess we could just add a dummy field..

BR,
-R

> > +
> >  extern const struct msm_perfcntr_group a6xx_perfcntr_groups[];
> >  extern const unsigned a6xx_num_perfcntr_groups;
> >
>
> --
> With best wishes
> Dmitry