[haiku-development] Re: (USB MIDI) Device hierarchy
- From: "Sean Collins" <smc.collins@xxxxxxxxxxx>
- To: haiku-development@xxxxxxxxxxxxx
- Date: Sat, 12 Feb 2011 19:03:30 +0000
> [Dealing with several arising points. Including apologies for maybe
> getting a little too conversational last night!]
>
> On Fri, Feb 11, 2011 at 01:47:35PM +0000, Ithamar R. Adema wrote:
> >
> > On Fri, 2011-02-11 at 13:09 +0100, Philippe Houdoin wrote:
> > > Which means probably that both usb_hid and usb_midi kernel
> > > drivers are
> > > accessing the device concurrently.
> > > It should be possible, but maybe we don't support it well right
> > > now.
> > >
> > > Please file a bug ticket for this issue, as it could be a deeper
> > > issue
> > > than just USB MIDI support.
>
> I've now received a configuration dump of the KX8 from Sean (made
> with
> usblyzer I think), that seems to show a very strange beast. It has
> two
> interfaces, an HID (Keyboard) interface, and a Yamaha-proprietary
> one,
> but no actual MIDI! MIDI must be handled in its own unique manner.
> So there's really no hope of getting it working.
>
> Why it should lock up the OS is another matter. I assume non-
> standard
> interfaces should be ignored?
>
> >
> > This issue has been a common one for other devices as well, e.g.
> > webcams
> > with a microphone, having both usb_audio and usb_video use it. The
> > best
> > solution for this I have been able to come up with is using the new
> > driver model, where drivers register against usb interfaces instead
> > of
> > the whole device.
> As far as I can see, this is what the usb_midi driver is currently
> doing.
> It finds the Interface, then the Endpoints in that, and connects to
> them.
> It shouldn't see any events on another Interface, should it?
>
> I assume the USB Stack itself merges outgoing events and demuxes the
> incoming stream to the relevant interfaces, mustn't it?
> >
> > It is possible to get it to work with the current usb
> > stack/architecture, but it is fairly tricky to get right IIRC...
>
> What more is needed?
>
> -- Pete --
FYI I filed a information request with Yamaha "not holding breath"
to see if they might be willing to share info. as I understand it this
design and driver model is used fiarly exsclusively in the yamaha line
of keyboards etc that have usb. So to support Yamaha usb devices it
would of course become mandatory to then support mine as well as many
others.all is not lost though. this keyboard does have a true midi
port. So its a workable situation, but aggrevating.
anyways I am asking around to see what I can turn up. they have a
MAC driver but no linux driver. They generally have a very non
opensource stance from my observation.
I do have some other devices we can try but does haiku have a proper
usb audio driver ? I have a lexicon omega that has usb audio and usb
midi and they are standard implementations. IE they both work without a
proper driver under windows using standard USB HID's.
Sean
Other related posts:
