CODEWITHSUNDEEP
linuxbluetoothhidbluez
NadavRub
NadavRub

Reputation: 2610

Linux, BlueZ, Initiating an hid BlueTooth Connection

Use-case

Question

In normal scenario, the HID Desc is reported through SDP, and thus, when the device connects to the keyboard it already knows the HID Desc to be used, in my use-case, the Virtual Keyboard ( Ubuntu machine ) initiate the connection, and thus, it's not triggered using SDP, Having that said, how should I send the device the HIDReport descriptor to be used? is it possible, at-all, to connect a keyboard to a device in this manner? Can I push the HID Report Desc to the Device ( to be controlled ) ?

Implementation

  1. Pair the device with the Ubuntu machine ( done manually )
  2. Initiate L2CAP connection on PSMs 0x11 & 0x13
  3. Handshake

All is working good so far, this is the point when I would expect to report the HID Descriptor to the device, but how exactly should this be done ?

Upvotes: 0

Views: 1639

Answers (1)

jmalmari
jmalmari

Reputation: 139

As far as I understand it, the HID host only reads the service descriptor once. Afterwards, you can initiate the connection yourself but you must conform to what you have previously told the host via SDP.

I have not come across a way to push the information to HID host later.

If you need to change something, you must clear the host's memory of the device ("uninstall device" in Windows, for an example) and reconnect (host initiating the connection), reading new information from updated SDP records.

If you don't need to change the HID descriptors, I believe you don't need to even have sdpd running after the initial connection. Ever.

Upvotes: 0

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