MIME-Version: 1.0
From:   Andrey Batyiev <batyiev@gmail.com>
Date:   Thu, 27 Dec 2018 05:21:10 +0200
Message-ID: <CAEQQxWzdBy9JOC7+oQTBJ35Gov1CDk17fy+XH=jha8MuT9fy9Q@mail.gmail.com>
Subject: Bluetooth ECDH selftest failed (endianness issue?)
To:     linux-bluetooth@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Sender: linux-bluetooth-owner@vger.kernel.org
Precedence: bulk

Hello everyone,

I'm trying to pair my MIPS based router with a phone (using bluez),
without success.
I have turned on debugging features of bluetooth kernel module and I
got this in dmesg:

[  234.481526] Bluetooth: Core ver 2.22
[  234.485231] Bluetooth: Starting self testing
[  234.525375] Bluetooth: ECDH sample 1 failed
[  234.529728] Bluetooth: Finished self testing

Also, I checked hcidump, and it seems that SMP "Pairing confirm"
command got rejected by the phone with an error ("Reason: Unspecified
Reason (0x08)").
As far as I understand, ECDH computation is involved in a pairing process.

However, my Linux desktop is able to successfully pair to the phone
(Ubuntu 18.04) via the same dongle, using same version of bluez.

The huge difference between my desktop and router is endianness:
router is big-endian, while desktop is little-endian. Maybe, that's
the case?

I'm not sure how to debug this, could you please advise?

Router specs:
CPU: QCA9531 (MIPS_24KC, big-endian)
Distro: OpenWRT git master
Linux: 4.14.88
BlueZ: 5.49
Bluetooth dongle: CSR8510 A10

Thanks,
  Andrey