Re: USB keyboard recognized as HID keyboard but doesn't work

From: Alan Stern
Date: Mon May 02 2011 - 18:29:14 EST


On Mon, 2 May 2011, Adi J. Sieker wrote:

> > Interestingly, the usbmon trace shows that the interrupt endpoint for
> > interface 1 isn't being used by usbhid. I don't know why, but it
> > shouldn't make much difference for your purposes since that interface
> > appears to be associated with the gaming interface. But maybe I'm
> > wrong and it is important somehow...
> >
> > The other noticeable thing is that the keyboard didn't accept the
> > Set-Idle request for interface 1.
> >
> > You said before that the keyboard worked okay when driven by a guest
> > Windows OS, right? Can you collect an equivalent usbmon trace for
> > that? Comparing the two traces may be instructive.
>
> I hope this is what you meant. :)
> Attached is a usbmon trace when I attach the keyboard to a VBox VM
> running a Windows XP guest. I have no idea how to get a USB trace from
> within Windows. The last block is when I pressed h twice in the Windows
> XP guest.

This is perfect. It shows that the H key is reported using the
interrupt endpoint on interface 1, which explains why it's not working
with usbhid. It also shows that the rejected Set-Idle request doesn't
matter.

At this point I don't know what the problem is, but now there's plenty
of information in the email thread for the people on linux-input to
debug this.

Alan Stern

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