Javier Martinez Canillas

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.

  • Projects

    Linux Kernel, U-boot
  • Role

    Senior Linux Kernel Developer

Posts by Javier Martinez Canillas

  • February 22, 2017 - Javier Martinez Canillas

    Samsung OSG Contributions to Linux Kernel 4.10

    Linux 4.10 was released on February 17; for this release, 6 engineers from the US and UK branches of the Samsung Open Source Group (OSG) contributed 341 patches that modified 44,709 lines of code. Again, most of the changes comes from Mauro Carvalho Chehab’s work to improve the Linux kernel documentation and fixing bugs all over the media tree. The following is a list 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 231 67.7% Javier Martinez Canillas 77 22.6% Stefan Schmidt 11 3.2% Shuah Khan 11 3.2% Luis de Bethencourt 10 2.9% Derek Foreman 1 0.3% OSG developers by changed lines Mauro Carvalho Chehab 44,120 98.7% Luis de Bethencourt 162 0.4% Javier Martinez Canillas 156 0.3% Stefan Schmidt 145 0.3% Shuah Khan 92 0.2% Derek […]

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  • December 15, 2016 - Javier Martinez Canillas

    Samsung OSG Contributions to Linux Kernel 4.9

    Linux 4.9 was released on December 11, making this release the biggest to date in number of changes. In this development cycle, the Samsung Open Source Group (OSG) contributed 394 patches that modified 15,856 lines of code. Although 4 engineers contributed to different Kernel subsystems, most of the changes comes again from Mauro Carvalho Chehab’s work to improve the Linux kernel documentation. The following is a list 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 238 60.4% Javier Martinez Canillas 108 27.4% Shuah Khan 24 6.1% Luis de Bethencourt 24 6.1% OSG developers by changed lines Mauro Carvalho Chehab 14,747 93.0% Javier Martinez Canillas 518 3.3% Shuah Khan 314 2.0% Luis de Bethencourt 277 1.7% OSG Contributions to This Release On this release, […]

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  • October 6, 2016 - Javier Martinez Canillas

    Samsung OSG Contributions to Linux Kernel 4.8

    Linux 4.8 was released on September 25, and in this release the Samsung Open Source Group (OSG) contributed 432 patches that modified 110,741 lines of code. Although 4 engineers contributed to different Kernel subsystems, almost all of these changes comes from Mauro Carvalho Chehab’s work to improve the media subsystem documentation. One noteworthy news item in this release is that another OSG member has been honored with a maintainer role, now that Luis de Bethencourt is taking maintainership of the BeFS filesystem. Javier Martinez Canillas is now listed as a reviewer for the Samsung Exynos ARM architecture. 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 347 80.3% Javier Martinez Canillas 69 16.0% Shuah Khan 11 2.5% Luis de Bethencourt […]

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  • September 1, 2016 - Javier Martinez Canillas

    Video Decoding with the Exynos Multi-Format Codec & GStreamer

    Exynos SoCs have an IP block known as the Multi-Format Codec (MFC) that allows them to do hardware accelerated video encoding/decoding, and the mainline kernel has a s5p-mfc Video for Linux2 (V4L2) driver that supports the MFC. The s5p-mfc driver is a Memory-to-Memory (M2M) V4L2 driver, it’s called M2M because the kernel moves video buffers from an output queue to a capture queue. The user-space enqueues buffers into the output queue, then the kernel passes these buffers to the MFC where they are converted and put it in the capture queue so the user-space can dequeue them. The GStreamer (gst) multimedia framework supports V4L2 M2M devices, but only for decoders the v4l2videodec element supports. Randy Li is working to also support M2M encoders in GStreamer (v4l2videoenc), but this hasn’t landed in upstream GStreamer yet. This post will explain how to use GStreamer and the Linux mainline kernel to do hardware […]

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  • August 1, 2016 - Javier Martinez Canillas

    Samsung OSG Contributions to Linux Kernel 4.7

    Linux 4.7 was released on July 27, 2016; in this release, 5 engineers from the Samsung Open Source Group (OSG) contributed 81 patches that modified 585 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 40 49.4% Mauro Carvalho Chehab 19 23.5% Luis de Bethencourt 15 18.5% Stefan Schmidt 4 4.9% Shuah Khan 3 3.7% OSG developers by changed lines Mauro Carvalho Chehab 242 41.4% Javier Martinez Canillas 181 30.9% Stefan Schmidt 90 15.4% Luis de Bethencourt 62 10.6% Shuah Khan 10 1.7% OSG Contributions to This Release For this release, Mauro contributed some fixes for the Media Controller Framework (MC) next generation, including a bug with the media device locking scheme […]

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  • May 23, 2016 - Javier Martinez Canillas

    Samsung OSG Contributions to Linux Kernel 4.6

    Linux 4.6 was released last week, and in this release, 4 engineers from the Samsung Open Source Group (OSG) contributed 200 patches that modified 7,556 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 97 48.5% Javier Martinez Canillas 57 28.5% Shuah Khan 36 18.0% Luis de Bethencourt 10 5.0% OSG developers by changed lines Mauro Carvalho Chehab 4533 60.0% Shuah Khan 1580 20.9% Javier Martinez Canillas 1425 18.9% Luis de Bethencourt 18 0.2% OSG Contributions to This Release In this release, Mauro continued his work on the Media Controller Framework (MC) to better support DVB devices; he was responsible for a lot of improvements in the MC framework to support entities […]

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  • March 24, 2016 - Javier Martinez Canillas

    Use a mainline U-Boot and non-signed kernels on Exynos Chromebooks

    In a previous post, I explained how to boot a mainline Linux Kernel to use a standard distribution on a Samsung Chromebook by installing it in the unused KERN-C and ROOT-C partitions of the internal eMMC. The kernel binary was contained in a signed FIT image since the read-only vendor bootloader can only boot signed images. The Many Ways to Boot Linux This is only one of the approaches that can be used to boot a mainline kernel. Another technique is to boot a signed u-boot image instead of a kernel, this process is called chain loading since the bootloader loads another bootloader rather than an operating system kernel. Non-signed kernels can be booted by chain loading a signed u-boot; this makes development easier and is more aligned with the development process on ARM platforms that don’t require verified boot. Another option would be to replace the stock vendor bootloader […]

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  • March 17, 2016 - Javier Martinez Canillas

    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 […]

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  • 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 […]

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  • November 23, 2015 - Javier Martinez Canillas

    Samsung OSG Contributions to the Linux Kernel 4.3

    Linux 4.3 was released two weeks ago; 5 engineers from the Samsung Open Source Group (OSG) contributed 168 patches that modified 4002 lines of code in a handful of 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 65 38.7% Mauro Carvalho Chehab 56 33.3% Luis de Bethencourt 44 26.2% Mario Smarduch 2 1.2% Stefan Schmidt 1 0.6% OSG developers by changed lines Mauro Carvalho Chehab 1823 45.6% Javier Martinez Canillas 1746 43.6% Luis de Bethencourt 345 8.6% Mario Smarduch 76 1.9% Stefan Schmidt 12 0.3% Mauro worked on cleanups and bugfixing in the media subsystem and considerably improved the media DocBook. Javier worked on cleanups and bugfixing in ARM Exynos support and fixed module autoloading for […]

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