I was looking for a list of keyboard scancodes in the linux kernel sources, but I did not find anything. Does someone know where to find these? Especially the USB scancodes would be interesting.
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The keycodes are in [src]/drivers/tty/vt/defkeymap.map:
# Default kernel keymap. This uses 7 modifier combinations.
[...]
See also my answer here for ways to view (dumpkeys) and modify (loadkeys) the current keymap as it exists in the running kernel.
However, those are a bit higher level than the scancodes sent by the device. Those might be what's in the table at the top of [src]/drivers/hid/hid-input.c, however, since they come from the device, you don't need the linux kernel source to find out what they are; they are the same regardless of OS.
"HID" == human interface device. The usbhid subdirectory of drivers/hid doesn't appear to contain any special codes, since USB keyboards are really regular keyboards.
One difference between keycodes and scancodes is that scancodes are more granular -- notice there's a different signal for the press and release. A keycode corresponds to a key that's down, I believe; so the kernel maps scancode events to a keycode status.
goldilocks
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Okay, that seems to be what I was looking for, thanks. But I still miss the actual scancode, probably I just mix up things. I learned [here](http://www.win.tue.nl/~aeb/linux/kbd/scancodes-1.html) that when I press ENTER on my USB keyboard, the scancode `1C` is sent to the kernel. But I don't seem to find `1C` in `/drivers/tty/vt/defkeymap.map`. Is there another layer between them? – defoe Nov 28 '13 at 15:02
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Whoops, I confused keycodes and scancodes -- have edited that in. Decimal `28` is hexadecimal `1C`. – goldilocks Nov 28 '13 at 15:23
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...notice `1C` is the IBM PC XT "Return pressed" from that wikipedia link. – goldilocks Nov 28 '13 at 15:27