With MidiDumpEnabled=1, only outputs MIDI dump to HDMI, every 31/32 input events

[nhemsley]

Strange one. I think this worked a couple of days ago on the same build.

It appears the midi keypresses are being output to hdmi stdio every 31/32 presses.

Sound works fine though, no latency.

Any ideas? Reformat?

Running on Raspberry PI 4 B

Edit: This is MiniDexed_2024-09-08-6c56960. I will reformat and try with the latest.

Edit: Reformatted, tried with MiniDexed_2024-09-29-8c18e60. Still the same problem.

[nhemsley]

Probably caused by this:

smuehlst/circle-stdlib#35

[probonopd]

@smuehlst do you know what's going on? Thanks

[smuehlst]

@probonopd Could you explain what MIDI dump to HDMI actually does? Is it in any way related to stdio? The problem with smuehlst/circle-stdlib#35 was that stdout was no longer line-buffered.
@nhemsley Why do you think that smuehlst/circle-stdlib#35 is related to this problem?

[smuehlst]

Further evidence that smuehlst/circle-stdlib#35 is unrelated:

• MiniDexed is using circle-stdlib v15.12 if I'm interpreting the submodule information correctly.
• The problem described in No output from printf() in samples/02-stdio-hello with v16.3 smuehlst/circle-stdlib#35 was introduced in circle-stdlib v16.3 and it was fixed in circle-stdlib v16.4.

[nhemsley]

@smuehlst, It is printf debugging of the midi codes coming in.

See here:

MiniDexed/src/mididevice.cpp

Lines 141 to 179 in 8c18e60

	switch (nLength)
	{
	case 1:
	if ( pMessage[0] != MIDI_TIMING_CLOCK
	&& pMessage[0] != MIDI_ACTIVE_SENSING)
	{
	printf ("MIDI%u: %02X\n", nCable, (unsigned) pMessage[0]);
	}
	break;
	case 2:
	printf ("MIDI%u: %02X %02X\n", nCable,
	(unsigned) pMessage[0], (unsigned) pMessage[1]);
	break;
	case 3:
	printf ("MIDI%u: %02X %02X %02X\n", nCable,
	(unsigned) pMessage[0], (unsigned) pMessage[1],
	(unsigned) pMessage[2]);
	break;
	default:
	switch(pMessage[0])
	{
	case MIDI_SYSTEM_EXCLUSIVE_BEGIN:
	printf("MIDI%u: SysEx data length: [%d]:",nCable, uint16_t(nLength));
	for (uint16_t i = 0; i < nLength; i++)
	{
	if((i % 16) == 0)
	printf("\n%04d:",i);
	printf(" 0x%02x",pMessage[i]);
	}
	printf("\n");
	break;
	default:
	printf("MIDI%u: Unhandled MIDI event type %0x02x\n",nCable,pMessage[0]);
	}
	break;
	}
	}

putting a manual flush in the code linked fixes this, but it's perhaps better to upgrade to the version that fixes the line buffering bug.

[probonopd]

@nhemsley could you please test the build at #758 (comment)?
Thanks.

[nhemsley]

I gave that a try, but the PI goes into a reboot cycle. I'll build locally and try that in a few hours.