Re: OS X USB/Midi Driver bugs?
Re: OS X USB/Midi Driver bugs?
- Subject: Re: OS X USB/Midi Driver bugs?
- From: "Jeff Schindler" <email@hidden>
- Date: Wed, 19 Jan 2005 00:39:59 -0500
This is for an unreleased proprietary USB MIDI device that doesn't have its
own driver, so it's using the OS X built-in driver. And I believe the
problem was seen on Jaguar (it was reported to me by a remote user). Could
an upgrade to Panther possibly fix this issue? Are there stand-alone
updates for the built-in driver?
Jeff
----- Original Message -----
From: "Kurt Revis" <email@hidden>
To: "Jeff Schindler" <email@hidden>
Cc: <email@hidden>
Sent: Tuesday, January 18, 2005 11:59 PM
Subject: Re: OS X USB/Midi Driver bugs?
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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