sound: Retire the MIDI sequencer

[christos]

Summary

The in-kernel MIDI sequencer is not used anymore, since this is done by
userland applications nowadays. It also contains bugs, and we are not
exactly sure how it works, or if it worked properly in the first place.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week

[christos]

Remove some more stuff from midi.c

[markj]

Does this removal warrant some post on -current or so to make sure no one's using it?

[christos]

In D50605#1155981, @markj wrote:

Does this removal warrant some post on -current or so to make sure no one's using it?

I've already sent an email to -multimedia and no one said they, or a port, is using it, but I can send to -current as well.

[christos]

In D50605#1155981, @markj wrote:

Does this removal warrant some post on -current or so to make sure no one's using it?

https://lists.freebsd.org/archives/freebsd-current/2025-June/007797.html

[christos]

Radio silence in the mailing lists. I take this as we are good to go. :-)

[christos]

Bump (also for the other MIDI patches).

[vishwin]

Won't be able to test till I fully get home from the K-W Hackathon next week. Just want to make sure userspace sequencing via audio/alsa-seq-server or audio/sndio (what I use) are not affected.

[vishwin]

pkgbase fails:

===> Creating FreeBSD-kernel-malvern-15.snap20250627004823
rm -f /usr/home/vishwin/boards/malvern/obj/usr/src/amd64.amd64/sourcestage/src.plist 2>/dev/null || :
/usr/src/release/packages/generate-ucl.lua  PKGNAME "src"  PKGGENNAME "src"  VERSION "15.snap20250627004823"  DESC "FreeBSD Kernel Sources"  COMMENT "FreeBSD Userland Sources"  PKG_NAME_PREFIX "FreeBSD"  PKG_MAINTAINER "[e-mail]"  PKG_WWW "https://www.FreeBSD.org"  /usr/src/release/packages/template.ucl  /usr/home/vishwin/boards/malvern/obj/usr/src/amd64.amd64/sourcestage/src.ucl
pkg -o ABI=FreeBSD:15:amd64  -o OSVERSION="1500048"  create -f tzst -l -1  -M /usr/home/vishwin/boards/malvern/obj/usr/src/amd64.amd64/sourcestage/src.ucl  -p /usr/home/vishwin/boards/malvern/obj/usr/src/amd64.amd64/sourcestage/src.plist  -r /usr/src  -o /usr/home/vishwin/boards/malvern/obj/usr/src/repo/FreeBSD:15:amd64/15.snap20250627004823
rm -f /usr/home/vishwin/boards/malvern/obj/usr/src/amd64.amd64/sourcestage/src-sys.plist 2>/dev/null || :
/usr/src/release/packages/generate-ucl.lua  PKGNAME "src-sys"  PKGGENNAME "src"  VERSION "15.snap20250627004823"  DESC "FreeBSD Kernel Sources"  COMMENT "FreeBSD Kernel Sources"  PKG_NAME_PREFIX "FreeBSD"  PKG_MAINTAINER "[e-mail]"  PKG_WWW "https://www.FreeBSD.org"  /usr/src/release/packages/template.ucl  /usr/home/vishwin/boards/malvern/obj/usr/src/amd64.amd64/sourcestage/src-sys.ucl
pkg -o ABI=FreeBSD:15:amd64  -o OSVERSION="1500048"  create -f tzst -l -1  -M /usr/home/vishwin/boards/malvern/obj/usr/src/amd64.amd64/sourcestage/src-sys.ucl  -p /usr/home/vishwin/boards/malvern/obj/usr/src/amd64.amd64/sourcestage/src-sys.plist  -r /usr/src  -o /usr/home/vishwin/boards/malvern/obj/usr/src/repo/FreeBSD:15:amd64/15.snap20250627004823
pkg: Unable to access file /usr/src/sys/dev/sound/midi/sequencer.c:No such file or directory
pkg: Unable to access file /usr/src/sys/dev/sound/midi/sequencer.h:No such file or directory
*** Error code 1

Stop.
make[4]: stopped making "create-source-packages" in /usr/src
*** Error code 1

Stop.
make[3]: stopped making "real-packages" in /usr/src
*** Error code 1

Stop.
make[2]: stopped making "real-packages" in /usr/src
*** Error code 1

Stop.
make[1]: stopped making "packages" in /usr/src
*** Error code 1

Stop.
make: stopped making "packages" in /usr/src/

My non-pkgbase machine has this applied but I have not tested for any MIDI regressions yet.

May also want to rebase after rG01addd846c64fc2c8be610d83bfdc84ddb57f2ec

[vishwin]

False alarm. Turns out pkgbase's plist logic relies on at least staging changes in git (no need to commit).

Userspace sequencing is confirmed not affected.