Re: [hatari-devel] MIDI IRQ handling bug

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 12/12/2021 à 14:23, Eero Tamminen a écrit :
> Hi Nicolas,
>
> Current Hatari IRQ handling is buggy for MIDI. Midi_UnInit() disables 
> MIDI IRQ, but Midi_Init() does not enable it, only calling Midi_Reset() 
> does, which does not happen on MIDI device change.
>
> (Similarly to handling of RS232, SCC & printer devices, MIDI device 
> change at run-time does not trigger reset.)
>
> I tried calling Midi_Reset() directly from Midi_Init(), but that freezes 
> Hatari at startup (to somewhere in interrupt handling code).
>
> Attached patch seems to work, but I assume all the things done by 
> Midi_Reset() should not be done just on device change.
>
> Could you look into what's the correct fix?

Hi

I didn't check why it fails when calling Midi_Reset from Midi_Init (but 
at early startup not everything is ready to handle interrupts), but 
nevertheless I don't think it matters as it's certainly a better place 
to call Midi_Reset when checking config's changes as you did.

We already call Cold_Reset if a config change requires it, so it seems 
ok to me to call Midi_Reset in that case.

As for all the variables reset in Midi_Reset beside just starting the 
timer, I don't think it's a problem ; it will just be the same as 
reseting any bytes that was currently transferred (ie we didn't receive 
all 8 bits yet), which doesn't seem a problem to me and acceptable in 
the case where the midi device was changed on the fly.

so, good to go :)

Nicolas