EAS on mediatek x20


I am considering buying the mediatek x20 and had a few questions:

  1. How much upstream support does the mediatek x20 have - kernel and AOSP android ? As in, will I be able to get Android going on the board using upstream code ?
  2. I assume there are pre-built images available for the board, which android dessert and kernel version are those based on ?
  3. For the deca-core scheduling are you using the energy aware scheduler (EAS) or some other scheme ? Is the code publicly available for the same ?
  4. Is the bootloader code available publicly ? My primary intention is to play around with the power management features and wanted to know if there are any blockers to modifying the PSCI/ATF/EL3 code such as security/signing etc.



Hi @kabhilash,

I’m afraid I cannot answer all your questions, but below are some info as I know:

  1. For X20 upstreaming, as I know Freedom has done some works for it: https://github.com/freedomtan/X20-96-board/wiki/booting-mainline-kernel

  2. Android release: http://builds.96boards.org/releases/helio-x20/mediatek/aosp/latest/, Kernel is 3.18: https://github.com/helio-x20/linux/tree/helio-x20

  3. You could download source code for kernel, IIUC the kernel has not enabled EAS.

  4. IIRC Bootloaders are not totally public. But Freedom has finished some works for ARM-TF for PSCI: https://github.com/freedomtan/atf-1.0-x20/tree/3fdcf7a6b3ca84185d4a985de98ce6a4d9c5f232

Leo Yan


Hi leo-yan,

Thanks very much for the reply. I took a look at the links and it seems that limited upstream x20 code is available. Is there any other armv8 based big.LITTLE board that you are aware of that I can use for my EAS experiments ? I see a hikey board but not sure if it will show dramatic improvements with eas since it is SMP. Any inputs would be appreciated


Hi @kabhilash,

AFAIK there have two public boards can be used for EAS profiling, one is Pixel phone, another is Juno board. Please note, usually when we do some EAS profiling works it’s also good to have GPU, CPUFreq/CPUIdle and audio playback these fundamental features. So it’s feasible to profile different scenarios.

Except X20 boards, other 96boards are almost SMP platform. Hikey is octa CA53 cores with SMP arch, so it can be used to verify EAS for SMP platform, but it’s not big.LITTLE architecture. You could monitor 96barods website in near term to check if have update for new 96boards.

Leo Yan