[Wlug] Seeking help with a USB barcode scanner

[Jamie Guinan]

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> 
> Hi Everybody,
> 
> Jamie Guinan wrote:
> > 
> >> See if "evdev" is loaded, then try reading the various 
> >> /dev/input/event* nodes.
> 
> Yes, evdev is loaded and I see some /dev/input/event* nodes.  The unique
> ones for this device (that show up when I plug in the device) are event3
> and event4.  Also, I see mouse1 and ts1.
> 
> > 
> >> I have a USB keyboard here.  Oh neat, under 2.6.19, they even give you 
> >> a path that matches the device ids,
> > 
> >> # od -x /dev/input/by-id/usb-1241_1203-event-kbd 
> >> (tap tap tap...)
> >> 0000000 92a9 460e 0000 0000 36dc 000b 0000 0000
> >> 0000020 0001 001c 0000 0000 92a9 460e 0000 0000
> >> 0000040 36e0 000b 0000 0000 0000 0000 0000 0000
> >> ...
> 
> In /dev/input/by-id, I see:
> usb-Cypress_Cypress_PS.2_Keyboard-event-{kbd,mouse}
> usb-Cypress_Cypress_PS.2_Keyboard-mouse
> 
> I tried your "od -x" trick on each of these to no avail.  I pointed the
> barcode scanner at some arbitrary barcodes, and it beeped and turned off
> the red light, but nothing appeared on my screen as a result of the "od -x".
> 
> Are there other possibilities to consider?

At this point I'd start putting printk's and turning on DEBUGs in the 
kernel source.  For starters,

 drivers/usb/input/hid-core.c:hid_input_report()
 drivers/usb/input/hid-input.c:hidinput_configure_usage()

I typically do something like this,

 $ make
 $ make modules_install INSTALL_MOD_PATH=$(pwd)/tmp
 (don't go installing under /lib just yet)
 $ rmmod foo
 $ insmod ./tmp/..../foo.ko
 [ unplug, replug, dmesg, tail messages, rinse, repeat ]

-Jamie