January 21, 2016 - Javier Martinez Canillas

Samsung OSG Contributions to the Linux Kernel 4.4

Linux 4.4 was released last week and on this release, 6 engineers from the Samsung Open Source Group (OSG) contributed 237 patches that modified 5762 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
Javier Martinez Canillas 98 41.4%
Luis de Bethencourt 89 37.6%
Mauro Carvalho Chehab 44 18.6%
Stefan Schmidt 3 1.3%
Derek Foreman 2 0.8%
Shuah Khan 1 0.4%
OSG developers by changed lines
Mauro Carvalho Chehab 3329 57.8%
Javier Martinez Canillas 1462 25.4%
Luis de Bethencourt 932 16.2%
Derek Foreman 32 0.6%
Stefan Schmidt 6 0.1%
Shuah Khan 1 0.0%

OSG Contributions to This Release

Mauro fixed a lot of issues and completed some clean up work on the media subsystem and improved its documentation. He also worked on the kernel-doc scripts to better format function typedefs and fix backward compatibility with older versions of Perl.

Javier fixed module autoloading on many SPI and I2C drivers, did a lot of cleanup on ARM Exynos and OMAP device trees, and added support for the Exynos5250 Snow Rev5+ Chromebook variant.

Luis fixed module autoloading on many platform drivers, fixed issues on different subsystems, and allowed many drivers to be compiled with COMPILE_TEST if there wasn’t a build dependency.

Derek provided fixes for the VC4 DRM driver (used in the RaspberryPi 2) to allow the vblank to be disabled and to use the fbdev CMA helpers to free and restore the framebuffer. These fixes were made as a part of our work porting Tizen to the RPI2.

Stefan improved the ieee802154 documentation and also fixed the ESC value for dispatch that was set to an older value defined in rfc4944 but later changed in rfc6282.

Shuah fixed a build issue that was present on a hwmon driver.

The Impact of the OSG

According to LWN’s report for v4.4 contributions, Samsung contributed a total of 670 patches that changed 16508 lines of code. This means that 35% of Samsung patches and modified lines came from the OSG. Luis and Javier both made it into the top 20 contributors for 4.4 by changesets.

Linux Kernel 4.4 contributors

The merge window for 4.5 is now open and a lot of patches from the OSG members are going in. The most interesting of these is the Media Control (MC) framework improvements made by Mauro with the help of others. This will allow proper support in MC for other types of V4L2 devices such as radio and TV, and is the foundation to allow other subsystems to use MC functionality (i.e: DVB, ALSA and IIO).

Javier Martinez Canillas

About Javier Martinez Canillas

Javier was a Senior Linux Kernel Developer for the Samsung Open Source Group. He has contributed to different kernel subsystems with a focus on ARM and Exynos SoC support. Besides hacking, he enjoys spending as much time as possible with his wife Tami and their twins, running, reading and writing technical articles like "Kbuild: the Linux Kernel Build System", published by the Linux Journal.

Image Credits: OSDC

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