Bluetooth Changes for Linux 3.9

Posted on March 18, 2013 by Gustavo Padovan

The 3.9 cycle in the Bluetooth subsystem was a way more calm than the previous ones. 49 non-merge patches were pushed upstream through bluetooth-next this time. The bulk of changes for this release comes from Johan Hedberg. Along with many fixes to the HCI Management code he also added support for 32 and 128 its UUID in the EIR data.

Other than that we only have fixes and clean ups from Andre Guedes, Andrei Emeltchenko, Gustavo Padovan, Rami Rosen and Szymon Janc.

One can always see all Bluetooth commits in the 3.9 with the following command line:

git shortlog –no-merges v3.8..v3.9-rc1 — net/bluetooth/ include/net/bluetooth/ drivers/bluetooth/

The 3.10 release is going to be a busy release for Bluetooth subsystem,so stay tuned!

BlueZ on Google Summer of Code 2012

Posted on March 25, 2012 by Gustavo Padovan

BlueZ was accepted to take part in GSoC 2012, if you don’t know what GSoC is, please go to its page and learn about.

We have already published our list of ideas, so if you are a student take a look there and check what might interest you. Then you can talk to one of our mentors to learn more about and work on a GSoC proposal.
You can get more information about BlueZ on GsoChere. Our contact info is on the same page.

We hope to have a great summer in this year’s Google Summer of Code.

Bluetooth Changes for 3.3

Posted on March 21, 2012 by Gustavo Padovan

The Linux 3.3 is out and it’s time to see what changed in the Bluetooth Subsystem, we had a quite big amount of changes this time, over 200 patches were merged during this release cycle.

The most noticiable change (in part due to the bugs it caused ;) was the move of the receive path handling from tasklets to workqueues. This was a long waited feature and will help a lot Bluetooth development from now and then.

In the L2CAP front Andrei Emeltchenko did a lot of clean up and added support for Extended Flow Specification(EFS) and Exteded Window Size(EWS). Johan Hedberg did a lot of Management changes, but biggest changes are landing in the 3.4 release when the Management Interface will be enabled by default.

Apart from that we have lots of LE changes, a new priority scheme inside HCI core, new socket option for L2CAP (BT_CHANNEL_POLICY). This list goes on, we had lots of changes. The shortlog can be seen with:

git shortlog -n v3.2..v3.3 — drivers/bluetooth/ net/bluetooth/ include/net/bluetooth/

Talk at Automotive Linux Summit

Posted on December 26, 2011 by Gustavo Padovan

About a month ago I’ve been to the Automotive Linux Summit in Yokohama, Japan to present about the BlueZ stack and how it would fit in a CarKit system. You can find the slides here. The conference was very nice, about 200 attendees and many interesting talks.

Also on Dec, 1st I attended the GENIVI Members Summit, where they created the Japanese working group of GENIVI.

Finally, I would like to thank Linux Foundation for sponsoring my travel to Yokohama.

The week at Prague

Posted on November 9, 2011 by Gustavo Padovan

At the end of October I’ve been to Prague, Czech Republic to take part in this year Bluetooth Summit to discuss the issues and the future developments of the BlueZ Project. It was the biggest BlueZ meeting we ever had, in total there was 21 people attending our summit.

The discussions were dominated by the next steps in the Low Energy, Bluetooth 3.0 + High Speed and BlueZ 5.0 (our next major release). On the LE energy side the discussion were in all parts of its stacks, there are pending patches for the interleaved discovery, Management commands for LE, RSSI and Tx power handling. and the development on GATT was one of the most discussed things.

On the BlueZ 5.0 side we are going to drop a lot of old stuff like pand and dund daemons, IPC mechanism for audio as well some of our DBus API we already marked as deprecated. In the management API side the idea is to finish it as soon as possible and enable it by default in the kernel, then some day in the future we can get rid of hciops and raw access to HCI sockets in bluetoothd.

My summit tasks are finish the L2CAP separation in sock and core parts and move the Bluetooth subsystem to use workqueues instead of tasklets. ;-)

After the Bluetooth Summit I attended the open day of the kernel summit, you can find nice reports of it in LWN here and here.

On Wednesday both LinuxCon Europe and Embedded Linux Conference Europe started. It was certainly a good idea to put both conferences together in the same place at the same time, I had the opportunity to meet people and see talks from both conferences. Some of the talks I took part were “Demystifying HTML5″ by Sulamita Garcia & Gustavo Barbieri, “The Linux NFC Subsystem” by Lauro Ramos Venancio & Samuel Ortiz. “systemd Administration in the Enterprise” by Lennart Poettering & Kay Sievers. “Linux for In-Car Infotainment” by Matt Jones.

Finally, I would like to thank ProFUSION to sponsor my travel to Prague.

Bluetooth Changes for Linux 3.1

Posted on October 5, 2011 by Gustavo Padovan

The 3.1 release is coming and it’s time to see what have changed in the Bluetooth subsystem. The biggest part of the changes are related to Bluetooth Low Energy, Andre Guedes worked in adding LE Adversiment cache support, all the remote devices found are cached in a list and after a defined timeout this list is flushed. Vinicius Gomes and Anderson Briglia added a initial implementation of the LE Security Manager Protocol. At the moment only JustWorks pairing is implemented.

Gustavo Padovan worked in another L2CAP refactoring patchset towards a clear separation between l2cap_core.c and l2cap_sock.c. Peter Hurley fixed a lot of potential deadlock over all the Bluetooth subsystem. Mat Martineau reworked the local busy handling inside the L2CAP Enhanced Retransmission Mode.

There is also many minor changes, fixes and clean ups, like HCI auth path fixes by Waldemar Rymarkiewicz, remote device blacklisting in the MGMT interface among many others.

A full changelog can be viewed issuing the following command in linus’ tree:

git shortlog -n v3.0..origin/master –no-merges net/bluetooth/ include/net/bluetooth/ drivers/bluetooth/

Bluetooth SAP Client into oFono and BlueZ

Posted on October 4, 2011 by Gustavo Padovan

During the last weeks I’ve worked in adding Bluetooth Sim Access Profile (SAP) Client Side support to oFono and BlueZ. This work was done by me at ProFUSION and sponsored by Linux Foundation.

The Bluetooth Sim Access Profile enables a device to use a remote SIM card as its own SIM card. Between the benefits are ability to user others features than phone calls, like data connections, SMS, etc. This is an advantage over the Handsfree Profile, that only supports phone calls. It also uses less power due to audio part, that is not streamed over the Bluetooth link like in the Handsfree Profile but instead is handled locally.

In the development I used the Telit UC864-G module. This module has built-in SAP Client support and other features that a common modem has to have.

The Telit modem has no Bluetooth support, then the main work was to modify oFono in order to connect a Bluetooth RFCOMM socket coming from BlueZ to a Serial port coming from Telit module. This Serial port give/receive SAP protocol messages. So anything we got from it can be passed without changes to the RFCOMM socket and vice-versa.

The work was divided in two parts, in BlueZ fd-passing support was added to the Serial API through a method called Serial.ConnectFD(). This was an already planned change by BlueZ developers for the upcoming BlueZ 5.0 release. This a generic method to get a RFCOMM socket, it can be used for any purpose or by any profile.

On the oFono side, the Bluetooth infrastructure plugin was used to create a new SAP plugin that is aware of any remote device with Bluetooth SAP Server support that we paired, it also tracks if any SAP Client enabled modem is available. If the two conditions holds true a new oFono modem instance is created to connect the paired device with the SAP enabled hardware. Of course, this modem works like any other oFono modem and one can do the usual phone operations with it.

The implementation inside oFono is modular enough to easily support any other SAP enabled modem that comes to the market in the future.

It’s important to note that all the work related to the SAP Client implementation is already upstream in both BlueZ and oFono repositories.

Finally, I would like to thank Denis Kenzior, oFono maintainer, by the help on reviewing and improving the SAP code.

GSoC: BlueZ projects sucessfullly finished

Posted on September 4, 2011 by Gustavo Padovan

During this summer four students took part in Google Summer of Code with BlueZ. All four have passed the final term and produced a lot of code. Each of them the wrote a report about their projects. The reports were posted in bluez.org. Here follows the links:

Improve EDS backend of Phone Book Access Profile (PBAP)
Student: Bartosz Szatkowski
Mentor: Claudio Takahasi

Nintendo Wii Remote Device Driver
Student: David Herrmann
Mentor: Gustavo Padovan

Implementing the Basic Imaging Profile(BIP)
Student: Jakub Adamek
Mentor: Vinicius Gomes

Implement the Video Distribution Profile(VDP)
Student: Prasad Bhat
Mentor: Luiz Augusto von Dentz

That is it for this summer, I’m hoping to have another great summer on GSoC next year.

Bluetooth Changes for Linux 3.0

Posted on July 8, 2011 by Gustavo Padovan

Yet another busy release. More than a hundred of commits for the Bluetooth subsystem will be in the upcoming kernel 3.0 release.

Those patches has the last bits for the Management Interface, By Johan Hedberg. There should be things to fix and minor features to implement, especially about Bluetooth Low Energy, but the hard work is done.

Another big set of changes is in the L2CAP layer, where Gustavo Padovan is rewritten some parts of it to remove the socket dependence from the L2CAP core. This will help fix many issues in the RFCOMM layer and will help the AMP Manager implementation.

Szymon Janc worked in add Out Of Band Pairing Support to the Management Interface and to replace the kernel_thread() usage with the kthread API among other fixes.

There is also support for 16 digit PIN code in the Legacy Pairing, and lot of bug fixing and clean ups.

Bluetooth changes for 2.6.38

Posted on March 15, 2011 by Gustavo Padovan

2.6.38 was a quiet release cycle for the Bluetooth subsystem, the biggest changes came from Johan Hedberg for the HCI management Interface, a under development code. Besides that we added support for two Atheros devices (AR9285 and AR5BBU12). Fixed a regression with the USB autosuspend and lot of other fixes and clean ups.

On the other hand 2.6.39 is being a very busy release cycle, stay tuned to see all the new stuff we will add to the Linux Bluetooth stack.

Gustavo Padovan

free as in freedom

Tag Archives: linux-bluetooth