Re: git: 32137c41065c - main - sound: Retire the version constants

On Fri, Sep 25, 2026 at 9:59 AM Christos Margiolis <christos@freebsd.org> wrote:
>
> On Fri Sep 25, 2026 at 6:27 PM CEST, Jason Harmening wrote:
> > On Fri, Sep 25, 2026 at 5:34 AM Christos Margiolis <christos@freebsd.org>
> > wrote:
> >
> >> On Wed Sep 23, 2026 at 10:19 PM CEST, Jason Harmening wrote:
> >> > On Wed, Sep 23, 2026 at 2:19 PM John Baldwin <jhb@freebsd.org> wrote:
> >> >
> >> >> On 9/22/26 14:54, Jason Harmening wrote:
> >> >> > Do you plan to also bump __FreeBSD_version__ for these changes?
> >> >> > This will break any out-of-tree sound driver that uses these macros,
> >> >> > particularly if you MFC it.
> >> >> > Such drivers will then need some way to determine whether to hardcode
> >> '1'
> >> >> > or use the previous macro/hardcode '5' to avoid a failed dependency
> >> >> check.
> >> >> > I still maintain such a thing, however few users there may be, and it
> >> >> seems
> >> >> > unsafe to assume there aren't others.
> >> >> >
> >> >> > This seems like a completely unnecessary change TBH.
> >> >>
> >> >> Can you use #ifdef to test if they are defined in an out-of-tree driver?
> >> >> In
> >> >> your case, perhaps as something like:
> >> >>
> >> >> #ifndef SOUND_MINVER
> >> >> #define SOUND_MINVER 1
> >> >> #endif
> >> >>
> >> >> <replying-all this time, god I despise the gmail UI>
> >> >
> >> > Sure, I mentioned that very possibility in my post on
> >> > https://reviews.freebsd.org/D59873.
> >> > That's still a hack, and I'm still not sure why it was necessary to kill
> >> > these defines in the first place.
> >>
> >> Does your driver actually depend on sound(4)'s versioning, and if yes,
> >> how?
> >>
> >
> > Uh, yes...just like all the in-tree drivers before you made this change, it
> > depended on those version constants to allow the module to load correctly.
> >
> > Of course I get what you're really asking here, and no...just like the
> > in-tree drivers, it does not make any functional distinction between
> > different sound(4) versions.
>
> So the versioning was functionally useless in your driver too.

> >>
> >> The reason for deleting those, although technically unnecessary, was
> >> because these values have been forgotten for years and do not actually
> >> mean anything useful, so I think it's better to just clean this up and
> >> fix the few (if any) use-cases, than keep this rotting further.
> >
> >
> > I completely understand that these no longer meant anything useful in terms
> > of KPI/KBI compatibility, but I don't really see why getting rid of them
> > was worth the churn, even just the in-tree churn (disregarding risks for
> > out-of-tree drivers).  What ongoing maintenance burden were these defines
> > likely to cause?
>
> There wasn't any significant maintenance burden, but that church wasn't
> anything complicated to implement either, and I don't see a point of
> keeping something that is functionally dead.
>
> > As a separate question, would it instead make sense to make these versions
> > start meaning something again?
> > For example, you recently made a change to require mixer_init() to be
> > called in a certain order relative to other initialization.  That change
> > seems perfectly reasonable from a technical standpoint, but would it also
> > make sense to bump the version constants to avoid a panic from loading a
> > stale audio driver kmod that didn't use the correct init sequence?
>
> This would be a good use case yes. I will think a bit more about it.

The odd choice to me is arbitrarily resetting the "epoch"; I see
justification for removing the macros that force everything to the
same value.  I can't think of precedent for resetting it back to 1 off
hand unless something were simultaneously renamed or moved, ensuring
there is never possible overlap.

> Christos
>