[alsa-devel] snd-serial-u16550 overflow problems?

r10 kindsofpeople r10kindsofpeople at hotmail.com
Tue May 8 21:36:07 CEST 2007

{reposting (with apologies) from alsa-user at another user's suggestion}

I'm having what appears to be overflow problems within the snd-serial-u16550 

I'm using 1.0.14rc1.

When calling "amidi -p hw:0,0,0 -s FILE.SYX" where hw:0,0,0 is the 
snd-serial-u16550 port,  the data coming from the serial port appears to be 
a small fraction (900 bytes) of the total file size (13000 bytes).

If I repeat the experiment, but send to a USB MIDI port, all is well.
If I send the data to the serial port using calls to 
snd_seq_event_output_direct(), and I add a 1 second pause between every 
sysex message, all is well (aside from it taking too long).
I'm logging data directly at the PC serial port using another PC, so I've 
eliminated the possibility that the serial-to-MIDI hardware is losing the 

My code is using blocking mode, and besides, amidi behaves the same way as 
my code.

I'm hesitant to blame the driver code (especially given that last time I did 
this, it was an interrupt configuration problem), but I could use some help 
figuring out where to look next.  Please?

Are there calls I can use to ensure that the previous message has gone out 
before writing the next one?  Given the amount of data I'm sending, should I 
be using snd_seq_event_output and scheduling the events on the queue?


More photos, more messages, more storage—get 2GB with Windows Live Hotmail. 

More information about the Alsa-devel mailing list