Re: Unloading a sound driver
Re: Unloading a sound driver
- Subject: Re: Unloading a sound driver
- From: Jeff Moore <email@hidden>
- Date: Tue, 21 Jan 2003 16:34:45 -0800
There are at least two processes that I know of that are around for the
entire login session that will retain references to all the audio
devices on the system:
- The LoginWindow process will have a reference to all the audio
devices in the system once an alert sound or an interface sound effect
is played.
- The SystemUIServer process will also have references to all the
devices if you use the volume keys on the keyboard or the menu bar
volume widget.
As B.J. says, kextunload ought to force things to unload. I'm not
certain as to how safe this option is. There may be issues if the
device is actively doing IO.
Another way that is 100% safe is to log out, and log back in as
">console". This will drop you into the console shell without the
window server running. From there, you can pretty much do whatever.
On Tuesday, January 21, 2003, at 03:43 PM, B.J. Buchalter wrote:
on 1/21/03 6:20 PM, Robert Penland at email@hidden wrote:
I read in a thread on this list back in June of 2002 that there was a
bug in
place that wouldn't allow an audio driver to be unloaded because the
system
was keeping an extra instance of the audio engine around. Has this
issue
been addressed in any of the newer OS releases? I still seem to see a
problem some of the time. If I play a sound that is directed to my
audio
driver, then even after it is over, the kextunload will fail, saying
there
is an instance of my audio engine still open. If, however, I don't
play a
sound after booting it will allow me to kextunload the driver. Is
there a
prescribed method for getting a sound driver into a state that will
allow it
to be kextunloaded?
In my experience, with current Mac OS X (ca 10.2 or 10.2.1), you can
kextunload your driver successfully. Even if apps are currently using
it.
You *may*, in some instances, have to run kextunload twice in a row
(once
gives an error, and the second time actually unloads the thing). Also,
if
you have apps that are actively looking at the device (e.g. Audio/MIDI
Setup), they may crash [again, not always, but some times]. But even
if they
do, all you have to do is relaunch. So, basically, it is not seamless
yet,
but it is close enough to get work done.....
Best regards,
B.J. Buchalter
Metric Halo
M/S 601 - Building 8
Castle Point Campus
Castle Point, NY 12511-0601 USA
tel +1 845 831-8600
fax +1 603 250-2451
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--
Jeff Moore
Core Audio
Apple
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