Synth limit On ESP32-P4?

[fesch]

When configuring more than 2 synths on my ESP32-P4, the core 0 makes a panic:

  // configure channel 1 --> OK
  amy_event e = amy_default_event();
  e.synth = 1;
  e.num_voices = 12;
  amy_add_event(&e);

  // configure channel 2 --> OK
  amy_event e = amy_default_event();
  e.synth = 2;
  e.num_voices = 12;
  amy_add_event(&e);

  // configure channel 3 --> PANIC!
  amy_event e = amy_default_event();
  e.synth = 3;
  e.num_voices = 12;
  amy_add_event(&e);

Consequently, when sending an event to synth=3, the core 0 panics too. My sustain pedal was sending control events to channels 1 to 3, so each time I pressed it, the ESP32-P4 rebooted :-|

[dpwe]

What I notice here is you don't specify any patch_number. AMY can't initialize the synth without knowing a patch (determines how many oscs etc). I think it rejects attempts to initialize a synth if the patch_number is missing, so maybe you have no synth 3 initialized. However, pedal to an unknown synth shouldn't crash it.

You are allowed to send synth + num_voices to a synth that has already been initialized with a patch number. That is interpreted as simply changing the number of voices. Synths 1 and 2 are initialized in the default config, so if you had features.default_synths set, the synth 1 and 2 stuff would have worked. But synth 3 is previously unknown, so you'll need to specify a patch num for it to be made real.

There should have been an error to STDERR, but you can only sometimes see that on an MCU.

[dpwe]

(it was a bug, fixed in #443)

[fesch]

Initializing the synth #3 with a patch_number works, yes. Thanks for that 👍

Sending anything to a not initialized synth results in the following error (probably not useful, but I put it here for completeness):

22:37:26.531 -> Guru Meditation Error: Core  1 panic'ed (Load access fault). Exception was unhandled.
22:37:26.567 -> 
22:37:26.567 -> Core  1 register dump:
22:37:26.567 -> MEPC    : 0x400079dc  RA      : 0x400079cc  SP      : 0x4ff1c640  GP      : 0x4ff0f680  
22:37:26.600 -> TP      : 0x4ff1cb00  T0      : 0x00000003  T1      : 0x4fffffff  T2      : 0x00000000  
22:37:26.600 -> S0/FP   : 0x00000010  S1      : 0x00000037  A0      : 0x00000001  A1      : 0x40040870  
22:37:26.600 -> A2      : 0x00000004  A3      : 0x000000ff  A4      : 0x40040870  A5      : 0x00000000  
22:37:26.600 -> A6      : 0x00000018  A7      : 0xffffffff  S2      : 0x00000004  S3      : 0x4ff11540  
22:37:26.633 -> S4      : 0x4ff1c6e4  S5      : 0x00000003  S6      : 0x00000000  S7      : 0x00000000  
22:37:26.633 -> S8      : 0x00000000  S9      : 0x00000000  S10     : 0x00000000  S11     : 0x00000000  
22:37:26.633 -> T3      : 0x4ff538cc  T4      : 0x00000004  T5      : 0x4ff14000  T6      : 0x4ff1c6e4  
22:37:26.633 -> MSTATUS : 0x80017880  MTVEC   : 0x4ff00003  MCAUSE  : 0x00000005  MTVAL   : 0x00000010  
22:37:26.667 -> MHARTID : 0x00000001