linux-kernel - Re: hid device not claimed but /dev/input/event exists

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Message-ID: <47BB1BD3.3040609@dbservice.com>
Date:	Tue, 19 Feb 2008 19:11:31 +0100
From:	Tomas Carnecky <tom@...ervice.com>
To:	Jiri Kosina <jkosina@...e.cz>
CC:	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: hid device not claimed but /dev/input/event exists

Jiri Kosina wrote:
> On Tue, 19 Feb 2008, Tomas Carnecky wrote:
> 
>> The device apparently has four 'interfaces' - whatever that is, see [1]. 
>> It seems like usbhid probes interface 2 (which is the LCD plus a few 
>> buttons, probably the four just under the LCD, as described [1]). 
>> Because usbhid doesn't know how to handle the buttons, it fails. But 
>> then it probes interface 3 which is a 'proper' HID device with 
>> well-defined buttons.
> 
> Yes, the dump clearly shows that.
> 
> Does anything appear in dmesg when you press those buttons? There should 
> be messages resembling the one you already have there:
> 
> drivers/hid/hid-core.c: report (size 8) (unnumbered)
> drivers/hid/hid-core.c: report 0 (size 8) =  00 00 28 00 00 00 00 00
> 
> and they should react to keys such as FastForward, Play, Mute, Volume Up, 
> etc.

Nothing. Not even after I removed the alsa-usb-audio driver. All I see 
is Keyboard.*, but the events from the speaker should be Key.*, right?

It looks like the speaker goes into a different mode once the USB cable 
is plugged in. Without the USB cable, the Z-10 acts as simple/dumb 
speaker, the volume up/down buttons change the internal volume, and I 
see that on the display, too. The play/next/prev song buttons don't do 
anything, which is quite obvious.
But once the USB cable is plugged in, the volume up/down buttons stop 
reacting. I assume they are now meant to send events to the computer so 
that some software can decide what to do. But features that are not 
useful for the computer (bass/treble), can still be controlled using the 
buttons on the speaker. The buttons are not dead. I can see that because 
the display goes to sleep after a few seconds of inactivity, and when I 
press the volume buttons, it wakes up and displays the current volume. 
So the speaker is definitely seeing that the buttons are being pressed.

Is there a USB packet inspector/dumper, like libpcap for network?

tom
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