Samsung OSG Contributions to the Linux Kernel 4.5

Linux 4.5 was released this week and on this release, 5 engineers from the Samsung Open Source Group (OSG) contributed 275 patches that modified 9,835 lines of code in different kernel subsystems.

The following list is all of the OSG engineers that contributed to this release and the number of changesets and lines of code as reported by Jonathan Corbet and Greg Kroah-Hartman’s gitdm tool.

OSG developers by changesets
Mauro Carvalho Chehab 170 61.8%
Javier Martinez Canillas 89 32.4%
Stefan Schmidt 7 2.5%
Luis de Bethencourt 6 2.2%
Shuah Khan 3 1.1%
OSG developers by changed lines
Mauro Carvalho Chehab 6501 66.1%
Javier Martinez Canillas 3046 31.0%
Stefan Schmidt 208 2.1%
Shuah Khan 67 0.7%
Luis de Bethencourt 13 0.1%

OSG Contributions to This Release

In this release, the work that Mauro has been doing for some time to extend the Media Controller (MC) API to use it for subsystems other than V4L2 (DVB and ALSA) has landed. This ended up being more than a simple extension and resulted in a big rework of the MC core and its API, so this work has been called the MC next generation. He also added MC support to the DVB subsystem and performed usual bug fixing and cleanup all over the media subsystem as a part of his maintainership duties.

Javier helped Mauro stabilize and test the MC next generation work by testing on different embedded platforms. A big part of his contributions are on the MC core and media platform drivers. He also worked on typical bug fixes and improvements for drivers, platform code, and device trees for ARM Exynos SoC based machines.

Shuah also helped with the MC next generation work by adding managed device resource (devres) support to allocate and free media devices. This will make it easier for different drivers (and subsystems) to share a common Media device and is needed for devices that have IP blocks registered on different subsystems but that must be exported to the user space as a single media graph.

Stefan worked on the 6lowpan networking subsystem, where he added Generic Header Compression (GHC) support and different compression modules for headers defined in RFC7400.

Luis did some bug fixing and cleanup in the SCSI, DRM and FBDEV subsystems.

The Impact of the OSG

According to LWN’s report for v4.5 contributions, Samsung contributed a total of 513 patches that changed 19,190 lines of code. This means that 54% of Samsung total patches and 51% of modified lines came from the OSG. That’s a striking number taking into account that only 5 OSG engineers contributed to this release. Mauro and Javier both made it into the top 20 contributors for 4.5 by changesets and Mauro alone accounted for 33% of all Samsung contributions in terms of changesets and changed lines which is impressive for a single person.

Samsung OSG Contributions to the Linux Kernel 4.5 - kernel-4-5-stats-combined

The merge window for 4.6 is now open and a lot of patches from the OSG members are going in. Most of this work is still happening in the media subsystem as part of our effort to finish and improve the Media Controller API next generation. We also have some improvements landing for the Exynos SoC support and new MC tests in the selftests framework.

Author: Javier Martinez

Javier Martinez Canillas was a Senior Linux Kernel Developer for the Samsung Open Source Group with a focus working on ARM and Exynos SoC support.