Re: [PATCH 0/4] ALSA: ump: Fix RPN/NRPN handling at MIDI 1.0 CC conversion

[Takashi Iwai <tiwai@suse.de>]

On Sun, 08 Nov 2026 13:47:47 +0100,
HyeongJun An wrote:
> 
> Hello Takashi,
> 
> As you asked in [1], this puts Alyandra's selector fix and my fixes for
> the other RPN/NRPN cases into one series, for both the UMP core
> converter and the sequencer.
> 
> Patches 1 and 2 are Alyandra's [2], without the KUnit test. Selecting
> an RPN now clears the NRPN selection and vice versa. Patches 3 and 4
> keep the selection after a send and clear only the data, drop data when
> nothing is selected, and handle a Null NRPN like a Null RPN.
> 
> What a MIDI 2.0 receiver gets, before and after the series:
> 
>   Input                                    Before             After
>   Null RPN, Data Entry, select RPN 0/1     RPN 0/0 = 0x40     nothing
>   Data Entry, select RPN 0/1               RPN 0/0 = 0x40     nothing
>   RPN 0/2 + data, data again, RPN 0/1      0/2, then 0/0      0/2, 0/2
>   Null RPN, Data Entry, select NRPN 0/5    NRPN 0/0 = 0x40    nothing
>   select RPN 0/0, NRPN 1/2 + data          RPN 0/0            NRPN 1/2
>   Null NRPN, Data Entry                    NRPN 127/127       nothing
>   select RPN 0/127, Null RPN, data         RPN 0/127          nothing
>   RPN 0/1 + data, CC 38, select RPN 0/2    0/1, then 0/0      0/1, 0/1
>   RPN 1/1 + data, RPN LSB 2, data          1/1, then 0/2      1/1, 1/2
>   Null RPN, RPN MSB 5, data                RPN 5/0            RPN 5/127
>   RPN 0/1 + data (unchanged)               RPN 0/1            RPN 0/1
> 
> The 0/127 row and the last two changes come from holding the RPN/NRPN
> numbers, as a MIDI 1.0 receiver does.
> 
> I checked the core converter with a local KUnit test over 35 input
> sequences. The 17 that changed are all of the kinds above, and the
> others give the same packets as before. The sequencer side was run
> with a legacy client sending CC and CONTROL14 events to a MIDI 2.0
> client on a patched kernel under qemu. That test will become the
> selftest, with Alyandra's cases added, as a separate patch.
> 
> Two cases are left as they were. A CC 6 alone waits for a CC 38 or
> the next CC 98 to 101, so a second CC 6 replaces the first instead of
> sending it. A CC 38 alone after a send waits the same way, and when
> the next CC 98 to 101 flushes it, it still goes out with MSB 0, now
> under the kept selection. Changing those would be a separate patch.
> 
> [1] https://lore.kernel.org/all/878q33y4z4.wl-tiwai@suse.de/
> [2] https://lore.kernel.org/all/20261107111056.667-1-alyandra5b@gmail.com/
> 
> Prepared with Claude Code (Claude Opus 5.5). Tested on x86_64.
> 
> Best regards,
> HyeongJun An
> 
> Alyandra Zahran Nadhir (2):
>   ALSA: ump: Clear stale RPN selector on NRPN change
>   ALSA: seq: ump: Clear stale selectors in sequencer conversion
> 
> HyeongJun An (2):
>   ALSA: ump: Fix RPN/NRPN state handling at MIDI 1.0 CC conversion
>   ALSA: seq: ump: Fix RPN/NRPN state handling at MIDI 1.0 CC conversion

Applied all patches to for-next branch now.  Thanks.


Takashi