Android Microconference

Much progress has been made upstreaming support for Android in the Linux kernel. During this Android microconference we'd like to continue working through the current Android patchset and plan for future Android related changes. The hope is that we'll be able to start getting front of the problem.

The conference will not be a standard presentation/speaker style, but a focused and active discussion between key players in the upstream kernel community and Google Android developers, focusing on the specific constraints Android faces, and how to resolve them in an acceptible upstream fashion.

This session was broken into two, this Android specific one, and another session focusing on Android Graphics, which can be found here:

• http://wiki.linuxplumbersconf.org/2013:android_and_graphics

• Etherpad for this session: http://etherpad.osuosl.org/lpc2013-android

• 2:00 - 2:05: Intro & Who’s who
• 2:05 - 2:35: Binder/KDBUS
• 2:35 - 3:15: Netfilter
• 3:15 - 3:30: Tea Break
• 3:30 - 4:00: Android Gadget/ConfigFS Gadget
• 4:00 - 4:45: Overflow/Head to the pub/Taxi to Airport

• Quick overview of kdbus & Greg’s ambitious plans
• Kay’s concerns regarding dbus focus.
• Any identified issues/blockers to running binder over kdbus?
• Next steps?
• Links:
  • kdbus
    • https://code.google.com/p/d-bus/source/browse/kdbus.txt
    • https://github.com/gregkh/kdbus
    • http://lwn.net/Articles/551969/
  • Binder:
    • https://lwn.net/Articles/466304/
    • http://lists.linuxfoundation.org/pipermail/ce-android-mainline/2012-January/000042.html

• Components, history, needed functionality
  1. idletimer
  2. qtaguid
  3. quota2
• idletimer upstreaming concerns?

Worried about abi w/ “Rename INTERFACE to LABEL in netlink notification”

• nfacct + owner as replacement for qtaguid?
  1. excessive iptables rules?
  2. manipulating iptables during normal operation?
  3. interface stats?
• What to do about quota2?
• Network namespace replacement for paranoid networking?
• Next steps?
• Links:
  • qtaguid - https://source.android.com/devices/tech/datausage/kernel-overview.html
  • nfacct - https://lwn.net/Articles/472094/
  • patch discussion - http://thread.gmane.org/gmane.linux.kernel/1362838/focus=1362967

• Core functional requirements
• Android Gadget “devices” (*=android kernel specific)
  1. Mass Storage
  2. Serial device
  3. RNDIS
  4. Ethernet
  5. ACM
  6. Functionfs (new adbd)
  7. ADB (legacy) *
  8. MTP *
  9. Android Accessory *
  10. Audio Source * (vs Gadget Audio driver, g_audio?)
• ADB device already implemented via functionfs w/ adbd userland
• Do we need similar userland conversion for MTP, Accessory and Audio Source?
• Does ConfigFS Gadget need functionfs support?
• What is left to do? Next steps?
• Links:
  • http://events.linuxfoundation.org/sites/events/files/slides/LinuxConNA2013-andrzej.pietrasiewicz-usb-gadget-configfs_0.pdf
  • https://wiki.tizen.org/wiki/USB/Linux_USB_Layers/Configfs_Composite_Gadget
  • http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/plain/Documentation/usb/gadget_configfs.txt

John Stultz john.stultz@linaro.org and Zach Pfeffer zach.pfeffer@gmail.com