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

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.

Christos