Re: USB Keypad

[Greg KH <greg@kroah.com>]

On Mon, Jul 06, 2026 at 08:08:01PM -0700, dave@synergy.org wrote:
> Excuse me. I have never sent e-mail to the Linux Kernel mailing list before.
> In reading the protocol, I think I should have sent my message to this one,
> instead.
> 
> Hello,
> 	I am working on a mobile device based on Raspberry Pi OS. I am using
> a USB keypad to navigate the UI of my device. I have purchased 2 models. One
> has 19 keys and the other has a few more. I've implemented the user-space
> code to read() the input device. Things are generally working fine. But I
> have one issue. On both models the keycodes I receive are not unique across
> all keys. On one, the key labeled INS and the one labeled 0 both send the
> same code.

That sounds like a broken device, not much the kernel can do about that.

Can you confirm this by looking at the keycodes when plugging the device
into any other "normal" Linux system?

> On the second one, the mapping is even more bizarre. It has
> duplicated Num Locks and other keys, as well. The number keys are always
> readable as such, but the other non-number keys can be aliased.

Again, is this keyboard issue?  Do they work properly anywhere else?

thanks,

greg k-h