Using HIDAPI, how can you query the raw report descriptor?

Question

I'd like to deconstruct the raw reports received from the hid_read function of hidapi.

As I understand, this can be achieved using the information from the device's report descriptors. But when trying to query for those descriptors, I get lost somewhere between the HID Spec and using the methods available in hidapi.

I would love to see a concrete C or node-hidapi based example that queries and enumerates all the report descriptors for a device — perhaps a mouse to keep things simple?

score 7 · Accepted Answer · answered Aug 02 '13 at 23:18

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I asked Alan Ott by email about this, and he responded with no as follows:

HIDAPI does not provide functions for getting or parsing the report descriptor. Since HIDAPI is for talking to a custom devices, these devices will likely contain all or mostly vendor-defined report items anyway.

answered Aug 02 '13 at 23:18

Shane Holloway

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Thanks, this was not really apparent from their docs! I had spend a lot of time trying to understand what is going on =) – user10607 Dec 12 '16 at 20:25

eatonphil · Answer 2 · 2015-03-17T12:12:40.933

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This isn't exactly what you're looking for, but it will get the same job done. I highly recommend you use libusbx over any other hid library. If you are willing to do so, here is a very blatant example of device enumeration.

Edit:

It appears that libusbx has been merged back into libusb. This is awesome! As the above link is broken, here is the new link.

edited Mar 17 '15 at 12:12

answered Jul 19 '13 at 14:46

eatonphil

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That looks fantastic — I'll take a deeper dive into it. – Shane Holloway Jul 19 '13 at 18:48
Feel free to check if you like it! :) – eatonphil Jul 24 '13 at 15:49
@eatonphil link you posted seems promising, but its broken.Can you repost it. – Raulp Mar 17 '15 at 03:56
@ShaneHolloway did you get through the solution?How about using lsusb -vv in the linux and get the information you desire to get. – Raulp Mar 17 '15 at 03:57
@Raulp, sure thing, just edited my post. Apparently libusbx has been merged back into libusb! – eatonphil Mar 17 '15 at 12:13
@eatonphil Can you please explain why you highly recommend using libusb over any other hid library? I would be curious to know what is the reason behind this recommendation. – Jean-François Beauchamp Jul 30 '18 at 16:13

score 1 · Answer 3 · answered Apr 14 '16 at 07:23

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I had success with using both https://github.com/Orochimarufan/HIDRAW/tree/master/HIDRAW_test (that is hopefully the C code example that you asked about) and RDD! USB HID Report Descriptor Decoder for more descriptive output.

answered Apr 14 '16 at 07:23

L.R.

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Using HIDAPI, how can you query the raw report descriptor?

3 Answers3