Re: Custom Midi USB Plugin: now two devices
Re: Custom Midi USB Plugin: now two devices
- Subject: Re: Custom Midi USB Plugin: now two devices
- From: Chuck Carlson <email@hidden>
- Date: Fri, 17 Sep 2010 07:26:31 -0700
Thanks, Brian and Doug,
The usb descriptor sounds like the problem. I'll change to make it custom for now.
The reason for the custom driver is to debug another problem. When the device is unplugged and replugged, it is taking 15 seconds for data to resume. The device is showing up right away in apps, but the data is delayed. This is causing much confusion for our customers, who need it running much sooner.
--Chuck
On Fri, Sep 17, 2010 at 1:18 AM, Brian Willoughby
<email@hidden> wrote:
On Sep 17, 2010, at 00:19, Doug Wyatt wrote:
On Sep 16, 2010, at 21:45 , Chuck Carlson wrote:
I'm customizing the SampleUSBMIDIDriver plugin and have added our usb vendor and product id and adjusted the parameters to MIDIDeviceCreate to add our manufacturer and product name.
But, now two devices appear in Audio Midi Setup. Seems as though the default handler and the new plugin are creating their own device.
How can I prevent this from happening?
So, your device's descriptors say it is USB MIDI class compliant, causing the class driver to grab it as well as your own driver? If so, then what are you trying to accomplish by having your own driver? The best (and maybe only) way to avoid the class driver is to not publish the descriptors it's looking for.
If that's not the problem, then maybe there's something you're misinterpreting about how MIDIDevice objects are normally created by drivers when first located, then during subsequent sessions marked online or offline by the driver, and generally only deleted by the user when s/he's sure they're never coming back?
As Doug alluded, the icons will be grayed out slightly in Audio MIDI Setup when offline. As a basic step when you're developing and change something critical like the VID/PID, you should unplug your device and delete all icons formerly associated with your device. If two icons appear when you plug the device in again, and they're both active, then you have a more serious problem.
P.S. Can't you simply provide your Manufacturer and Product name in the USB String Descriptors? That might be the more standard way to identify your device. There's generally no need to programmatically add manufacturer and product names, at least not with driverless USB-MIDI devices.
Brian Willoughby
Sound Consulting
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