Re: Discussion [MIDI USB X-Files Episode]
Re: Discussion [MIDI USB X-Files Episode]
- Subject: Re: Discussion [MIDI USB X-Files Episode]
- From: Doug Wyatt <email@hidden>
- Date: Mon, 23 Sep 2002 17:42:47 -0700
I occasionally see strange behavior like this too but it seems that I
have subconsciously trained myself to do something that makes it not
happen :-(
There were some USB fixes from 10.2 to 10.2.1. I will have to research
them to see how they may or may not be relevant.
It's possible that the sample and MIDI class drivers may not be
shutting down their USB user clients correctly. I will look into this.
I get intermittent reports of MIDIServer crashing on exit; this could
be exacerbating the problem because a crash on exit usually means that
drivers are not tearing down their USB user clients and relying on
whatever failsafes are in the USB stack.
I'd like to know if you're on 10.2 or 10.2.1 ... or, if you're on
10.1.5, I believe the panic is a known issue and ... well, somehow I'm
guessing there will not be a 10.1.6.
Doug
On Friday, Sep 20, 2002, at 14:24 US/Pacific, Michel wrote:
On Friday 20 September 2002 21:43, Andy wrote:
Do we actually need/want a discussion or am I being paranoid ?
It does appear that something may be awry somewhere in the bowels of
the MIDI server. Or that driver writers, (like me) are not quite
aware of the whole story.
Indeed, with that setup:
+ 1 Roland sc8820 (3 in/outs, with a roland driver, but that probably
acts as
a nub)
+ 1 EZBus (3 in/outs)
+ 2 Evolution keyboards (1 in/out each)
That and the usual set of hubs, mouse etc on USB.
Note that all of those devices (save the roland, but that driver has
been
tested for >1 year) are 'compliant': they don't use a third party
driver.
Regularly one or the other peripheral vanishes from CoreMIDI
awareness. Note
that I do quite a lot of launch/quits of MIDI apps, so the server does
a lot
of restarts.
When a device diseapears:
+ Power cycling the device doesn't fix the problem.
+ Unplugging/replugging the device doesn't fix the problem
+ Quitting all MIDI apps to kill the MIDI server doesn't fix the
problem.
Sometime, you can recover it by one of those 3 methods, but most of
the time
you need to reboot.
Also, when the machine is in that 'forgetful' state, it has become
quite
common that the machine will panic at some point, preferably when I
wake it
up the next day.
It is hard to analyse what is the cause of that. For example, the
EZbus is
also a USB 'soundcard' (2 * 24/48Khz); if MIDIserver 'forgets' EZbus
exists,
the USB sound still works fine. It means it's not the device that is
crashed
somehow.
Another interesting point is that one of the Evolution keyboard
(MK-225C) has
a led display that blinks in a certain way if it is reset via USB. And
regularly I see that keyboard getting reset for no apparent reason,
usualy
while playing it.
Given the 'smoky' feel of those issues, it's hard to file a bug
report. If
you have any strange experience with your device, please contribute
them so
we can nail that one down!
--
Doug Wyatt
work: email@hidden (CoreAudio)
personal: email@hidden
http://www.sonosphere.com
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