Ubuntu

Handling hardware solely from the android img files

Registered by Oliver Grawert

The Ubuntu Touch rootfs should be as generic as it can get by moving all hardware specific files into the android system image.
This also requires having a mechanism to overlay the hardware specific device configurations inside the rootfs on boot (by copying or by bind mounting the properly configured files on top from /system/...)

Blueprint information

Status:
Not started
Approver:
Michael Frey
Priority:
Undefined
Drafter:
Oliver Grawert
Direction:
Approved
Assignee:
Oliver Grawert
Definition:
Approved
Series goal:
None
Implementation:
Unknown
Milestone target:
None

Related branches

Sprints

Whiteboard

currently used files:
* /lib/udev/rules.d/70-android.rules (currently bind-mounted by the touch initrd script from /usr/lib/lxc-android-config/70-$device.rules)
* /lib/modules (currently bind-mounted from /system/lib/modules by the touch initrd script)
* /usr/share/alsa/ucm/$sounddevice (shipped by alsa-lib, we used to try to keep these bits in the package for easier upstreaming as we usually do for this package)
* /etc/ubuntu-touch-session.d/* (shipped by ubuntu-touch-session for defining resolution and webkit scaling factor per device.
* /usr/share/powerd/device_configs/config-$device.xml (shipped by powerd as is)
* /usr/share/apparmor/hardware/graphics.d/apparmor-easyprof-ubuntu_$device (currently shipped as-is by lxc-android-config)
* /etc/init/boot-hooks/set-display-mir.conf (hardcoded whitelist of devices to enable Mir by default, probably easiest to just drop this and always default to Mir (shipped as is by lxc-android-config))
* everything related to bluetooth ... while we have some basic bringup running inside the container we still need upstart jobs for bringing up per-device BT configs on the Ubuntu side)
* /usr/share/apparmor/hardware/video.d/apparmor-easyprof-ubuntu_$device (not sure the files there are still needed, if so, we definitely miss some arches here (shipped as is by apparmor-easyprof-ubuntu))

---

A proposal:

Ship an ubuntu "Shadow filesystem" in the android system.img that is used to overlay the files on the rootfs and processed from the initrd script with something similar to:

for file in $(find /system/ubuntu-shadow); do
    target=$(echo $file|sed -e 's/^/system/ubuntu-shadow//')
    source=$file

    # make sure target files and dirs exist etc ...

    mount --bind $source $target
done

(?)

Work Items