Hi list,
Takashi Iwai <[EMAIL PROTECTED]> wrote:
[..]
> > Normally, according to the M3r's SysEx implementation in its manual,
> > this should give the same output, exactly 23963 bytes.
> > However, the second version loses about 130 bytes during the transfer.
> > The strange thing is that the beginning of the data (SysEx header:
> > F0 42 30 24...) is fine, and starting around byte 700 the data is exactly
> > the same as in the correct output, including the EOX (F7) at the very end of
> > the output. But somewhere in this first part, data is lost.
>
> just to be sure: any realtime events can come in?
No, I checked that. The M3r sends active sensing (0xfe), but I filtered that out.
In the data I get the only MIDI bytes > 0x7f are the F0 at the start and the
0xF7 at the very end. Also, I think a SysEx message cannot be interrupted by
any other message, right?
> > This number was observed to be in a range of +-20 bytes.
> > Could anyone explain this? Though the MIDI interface on the PC side
> > is in a cheapo Soundblaster PCI512 card, I don't think it's responsible
> > for data losses. To me this looks rather like a rawmidi problem. The
> > program really doesn't do much more but snd_rawmidi_open, snd_rawmidi_write,
> > snd_rawmidi_read, snd_rawmidi_drain and snd_rawmidi_close.
>
> as Clemens wrote, please check the buffer overruns.
> the buffer overruns are shown in /proc/asound/card0/midiX proc file
> but only during the midi is opened for read.
I checked that - no overruns during the whole transfer. At the end of
the transfer (but before the device is closed) I see:
franky@faramir:/proc/asound/card0> cat midi0
EMU10K1 MPU-401 (UART)
Output 0
Tx bytes : 7
Mode : native
Buffer size : 4096
Avail : 4096
Input 0
Rx bytes : 23860
Buffer size : 4096
Avail : 24
Overruns : 0
The 24 avail input bytes are ActiveSensing bytes.
I have attached the small program to this mail for your studying
pleasure :-}. If anything is wrong, I'd certainly love to hear about
that. This is the first ALSA rawmidi program I've written.
I'll dive into the M3r's SysEx docs and the dump I get once more; maybe
there is something I overlooked.
Thanks,
Frank
/*
* m3rx: Small ALSA-based (using rawmidi API) program to get a complete bulk dump from
* a Korg M3r expander module. No checksums, no flow control, nothing yet.
*
* Copyright (c)2003 Frank Neumann
*
*/
#include <stdio.h>
#include <stdlib.h>
#include <alsa/asoundlib.h>
#define ST_START 0x00
#define ST_IN_SYSEX 0x01
#define ST_DONE 0x02
/*** START OF MAIN FUNCTION ***/
int main(int argc, char* argv[])
{
int err, state, numbytes;
unsigned char ch;
unsigned char sysex_get_all[] = { 0xf0, 0x42, 0x30, 0x24, 0x0f, 0x00, 0xf7 };
FILE *fp1;
snd_rawmidi_t *raw_in = 0, *raw_out = 0;
if (argc != 2)
{
fprintf(stderr, "Usage: %s <outputsysexfilename>\n", argv[0]);
exit(5);
}
fp1 = fopen(argv[1], "w");
if (fp1 == NULL)
{
fprintf(stderr, "Unable to open output file '%s'\n", argv[1]);
exit(5);
}
err = snd_rawmidi_open(&raw_in, NULL, "default", 0);
if (err)
{
fprintf(stderr,"snd_rawmidi_open 'default' failed: %d\n", err);
exit(5);
}
err = snd_rawmidi_open(NULL, &raw_out, "default", 0);
if (err)
{
fprintf(stderr,"snd_rawmidi_open(2) 'default' failed: %d\n", err);
exit(5);
}
fprintf(stderr, "rawmidi device opened sucessfully.\n");
fprintf(stderr, " Now sending ALL DATA DUMP REQUEST...\n");
snd_rawmidi_write(raw_out, &sysex_get_all, sizeof(sysex_get_all));
snd_rawmidi_drain(raw_out);
fprintf(stderr, "[Waiting for SysEx sequence to start]\n");
state = ST_START;
numbytes = 0;
while (state != ST_DONE)
{
snd_rawmidi_read(raw_in,&ch,1);
switch(state)
{
case ST_START:
if (ch == 0xf0)
{
fprintf(stderr, "[SysEx start code found, writing data]...\n");
state = ST_IN_SYSEX;
fputc(ch, fp1);
numbytes++;
// fprintf(stderr, "\r%06d bytes written... ", numbytes);
}
break;
case ST_IN_SYSEX:
if (ch < 0x80)
{
fputc(ch, fp1);
numbytes++;
// fprintf(stderr, "\r%06d bytes written... ", numbytes);
}
else if (ch == 0xf7) /* EOX */
{
fputc(ch, fp1);
numbytes++;
// fprintf(stderr, "\r%06d bytes written... ", numbytes);
fprintf(stderr, "\n[SysEx EOX code found, finishing - %d bytes written]\n",
numbytes);
state = ST_DONE;
}
break;
default:
break;
}
}
snd_rawmidi_drain(raw_in);
snd_rawmidi_close(raw_in);
snd_rawmidi_close(raw_out);
fclose(fp1);
}
