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Android Linux

Project To Mainline Android Kernel Changes Formed 73

Posted by Unknown Lamer
from the keep-on-merging dept.
ghostoftiber writes "From the article: 'Tim Bird, a Sony engineering veteran and the chair of the Architecture Group of the Linux Foundation's CE Workgroup, has announced a new concerted effort to get Android's changes to the Linux kernel back into the mainline Linux kernel tree.' Android has been using Linux 2.6.x for its devices since its release, with patches from Google. To date they haven't been merged back into the kernel mainline but existed on kernel.org. Some of the features such as wakelocks would help with Linux tablet projects, but other features aren't fully realized and support remains spotty. The radio interface layer ... still exists as an ATI/Nvidia-esque shim loader scheme with modem 'drivers' being nothing more than ihex files loaded by open code."
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Project To Mainline Android Kernel Changes Formed

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  • Attention! (Score:3, Informative)

    by Anonymous Coward on Wednesday December 21, 2011 @01:55PM (#38450832)

    Android has been using Linux 2.6.x for it is devices since it is release, with patches from Google.

    Editors, please edit. Just once. Please.

  • RIL? Kernel? (Score:5, Informative)

    by Andy Dodd (701) <atd7@@@cornell...edu> on Wednesday December 21, 2011 @01:57PM (#38450854) Homepage

    On nearly all devices the RIL is in userland.

    On Samsung GalaxyS devices, the modem was attached to a serial port and the RIL translated Android RIL function calls into modem AT commands. The kernel part of the radio interface was a serial port driver, nothing more.

    Same for most HTC devices, although some that used Qualcomm MSM implemented a pseudo-tty implemented over shared memory - but it was still AT commands being transferred. Other Qualcomm AMSS functions were implemented using an RPC-over-shared-memory interface, the kernel portion of this was small.

    Galaxy S II devices (at least GSM Exynos-based ones) have the radio hung as a USB device off of the CPU, so it did require a driver to implement. Still, most of the RIL is in userland, and the RIL belongs there.

  • Re:Oh, no. (Score:3, Informative)

    by GuB-42 (2483988) on Wednesday December 21, 2011 @02:37PM (#38451296)

    Linux is everyone's playground.

    Google and the mainline developers hold different point of view. For Google, the kernel is just a component of their OS, this is the reason why they can get away with hacks that mainline developers view as brain damage. They just need to get it to work with Android.

    Trying to merge the mainline kernel with Android is just a bonus witch benefits both parties.

  • by Anonymous Coward on Wednesday December 21, 2011 @03:20PM (#38451758)

    I assume you meant Radio Interface Layer but it took a while to figure that out. I figure I'll just help people out a bit.

  • by Andy Dodd (701) <atd7@@@cornell...edu> on Wednesday December 21, 2011 @03:29PM (#38451860) Homepage

    Correct, RIL = radio interface layer in this case. I was responding to this in the summary:

    "The radio interface layer ... still exists as an ATI/Nvidia-esque shim loader scheme with modem 'drivers' being nothing more than ihex files loaded by open code."

    Now, in many cases, it is correct that hex files are being loaded by open code on initialization... but the radio baseband firmware of any phone I know of has NEVER been open source. All they are doing is bootloading a separate radio chipset, which has its own processor. It's another thing that doesn't belong in the kernel (you want scary? I have seen some cases where device firmware is stored as gigantic C arrays in header files... An example of something that should NOT be in the kernel...)

Fools ignore complexity. Pragmatists suffer it. Some can avoid it. Geniuses remove it. -- Perlis's Programming Proverb #58, SIGPLAN Notices, Sept. 1982

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