[PD] [PD-announce] hidraw v0.1.0 released.

Albert Rafetseder albert.rafetseder at univie.ac.at
Tue Nov 8 12:26:27 CET 2022

>> Just tested hidraw on my linux laptop (latest deken version)
>> Strangely, when I click [listdevice( message in help file, i get in 
>> console the same device listed 14 times :
> I've seen some same devices appear 2, 3 or 4 times. Not sure why is
> this happening but is related to https://github.com/libusb/hidapi. I
> just use their function to list devices.

This should be fine. Indeed, ...

> eventually you can check that "Usage (page):" is different in each
> dup. not sure what this means or how to use it.

Some explanatory snippets:

"""Usages are part of the HID Report descriptor and supply an 
application developer with information about what a control is actually 
measuring or reporting.""" (from 
https://www.usb.org/sites/default/files/hut1_3_0.pdf )

"""HID devices exchange data with the host computer using data bundles 
called “reports”. Each report is divided into “fields”, each of which 
can have one or more “usages”. In the hid-core, each one of these usages 
has a single signed 32 bit value.""" (from 
https://www.kernel.org/doc/html/v5.6/hid/hiddev.html#the-hiddev-api )

E.g., [hidraw] shows two entries for my USB mouse, with:
* Usage (page): 0x2 (0x1), making it a "Mouse" from the "Generic Desktop 
* Usage (page): 0x1 (0x1), making it also a "Pointer" from the same Page

(My laptop's touchpad produces a dozen or so list entries as well. It's 
a Mouse, a Pointer, a Digitzer for Fingers, and Vendor-Defined ... :-)

By the way, Linux's `lsusb -v` shows similar information to 

Best regards,

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