[wdmaudiodev] Re: Dynamic subdevice creation
- From: "Jeff Pages" <jeff@xxxxxxxxxxxxxxxx>
- To: <wdmaudiodev@xxxxxxxxxxxxx>
- Date: Fri, 5 Dec 2008 10:54:32 +1100
Thanks for your suggestions, Uwe and Eugene.
In my application I don't have a convenient IRP I can use when an audio
component appears on the broadcast multiplex, but out of curiosity I tried
passing NULL as the IRP pointer to IPort::Init and it appears to work okay
on both XP and Vista. I'd still sleep easier if I knew this was really an
acceptable thing to do. Does anyone know if IPort::Init actually does
anything with the IRP pointer?
I note Eugene's comment about "only a few dynamic subdevices". In my case
that's probably okay, as the number of audio services that can be
transmitted on a DAB multiplex is fairly limited, even with the new DAB+
version. I'll see how I go with it, but I'd really prefer to avoid all the
overhead of creating a buss driver if I can. I've taken note of Mitch's
advice from January 2007 about the order in which subdevices and physical
connections need to be registered and unregistered, so hopefully it'll be
okay.
Jeff
----- Original Message -----
From: "Uwe Kirst" <u.kirst@xxxxxx>
To: <wdmaudiodev@xxxxxxxxxxxxx>
Sent: Thursday, December 04, 2008 8:27 PM
Subject: [wdmaudiodev] Re: Dynamic subdevice creation
Jeff Pages schrieb:
I'm developing the driver for a digital radio receiver card which needs
to dynamically create audio subdevices for each audio channel it finds on
the broadcast multiplex. However in creating a subdevice I need to call
IPort::Init which requires a pointer to the IRP_MN_START_DEVICE Irp the
driver received on startup, but by the time everything's running and it's
identified the various audio components on the multiplex, that Irp has
long gone.
I have successfully used another irp for that purpose: the irp from my
device ioctl function which toggles the subdevice creation. Seems to work
here.
/Uwe
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