Re: OS X USB/Midi Driver bugs?
Re: OS X USB/Midi Driver bugs?
- Subject: Re: OS X USB/Midi Driver bugs?
- From: Kurt Revis <email@hidden>
- Date: Tue, 18 Jan 2005 20:59:14 -0800
On Jan 18, 2005, at 7:22 PM, Jeff Schindler wrote:
Can anyone tell me if there are known bugs regarding sending SysEx
messages over USB MIDI ports under OS X? We have an app sending SysEx
messages to a device in which it appears that the 256th byte is
quietly dropped. We've confirmed this also with SysEx Librarian.
Both of the apps send the SysEx messages correctly via non-USB MIDI
ports. Any help is much appreciated.
What MIDI interface are you using? Does it have its own driver, or
does it use the OS X built-in driver? What version of OS X?
It's sadly not uncommon for MIDI device drivers to have problems
sending and receiving sysex. Some of my users have reported having
every 4th byte dropped, or 2 bytes dropped out of every 256, or similar
(but harder to track down) issues. Generally, updating the driver
software or switching to a different MIDI device makes the problem go
away.
I don't think there is a general systemwide problem, since I have
managed to send and receive a bunch of sysex successfully, and I hear
from plenty of users who do the same. The majority of that is over
USB. I just get the impression that some driver authors don't do much
testing of sysex.
(It's astonishing that this is still a problem in 2005. My machine can
reliably send megabytes of data over a wireless connection, and yet
it's difficult to send a few kb over a plain old wired serial
connection?)
--
Kurt Revis
email@hidden
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