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ARM/Hummingbird
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Nexus S
So, I have a barebones version of MeeGo (barely) running on the Nexus S. I can't really do much with it on my own, but I'm posting the info here so you can build it and try it for yourself.
What works
- ADB root shell
- X11 & UI apps
- Screen brightness
What doesn't work
- Touchscreen
- WiFi
- Anything else :-P
Build
- Use the procedure here to generate an ext2 image, and copy it to linux/rootfs.ext2 on the internal memory of the Nexus S. http://wiki.meego.com/ARM/Meego_on_Beagleboard_from_scratch#Build_the_rootfs
I have my boot.img (kernel + ramdisk) and a MeeGo kickstart file at http://blog.steventroughtonsmith.com/2011/01/nexus-s-meego.html; you can use fastboot to boot the image, or flash it to the recovery partition to dual boot. The actual MeeGo rootfs is run from a rootfs.ext2 file you can drop onto the Nexus S using Mass Storage mode - no need for messy flashing or the like, you can thank me later).
There's not much else I can do on my own right now, so if you want to see anything become of this do get involved!
Kernel
My kernel is Samsung stock; you will need to modify it to get X11 to run:
- git://android.git.kernel.org/kernel/samsung.git
- make herring_defconfig
The only change was modifying the .config file to turn on CONFIG_VT (needed for X11, unless we recompile X11 without VT support).
Screen brightness
Will add this to a newer kickstart, but for the time being, you can bring the brightness to full by doing:
- echo 255 > /sys/devices/platform/s3cfb/spi_gpio.3/spi3.0/backlight/s5p_bl/brightness
Notes
dmesg output is available on Talk:ARM/Hummingbird.
Samsung Galaxy Tab
Meego
Current Status
Working:
- Boots Meego (external SD btrfs partition or ext2 loop file)
- Wifi working (so you can login)
- Tab kb dock working (so you can login)
Not working:
- Starting X - no errors, but no display, investigating currently, help appreciated! :)
Not tried yet:
- PowerVR accelerated UI
- Bluetooth
- Modem
- GPS
- Camera
- Sound
- Everything else too!
If you would like to help, have questions, ideas, etc., please catch me (lardman) in #meego-arm
Introduction
The idea here is to boot Meego from the external SD card (similar to the N900 Meego boot process.)
Currently this requires that you flash a new, slightly modified, kernel to your Tab.
The Tab kernel contains an initramfs which contains an Android version of init which brings the system up.
With Android devices, there is normally a hardware key you can press at boot time to specify whether you want to enter flashing mode or recovery mode (and no keypress indicates a normal startup.) On the Tab the flashing key is the volume down button and the recovery button is the volume up button.
With most Android devices the normal and recovery boots load different kernels (located on different partitions.) This is nice as it means one does not need to modify the normal Android kernel at all, but can still mess about with other kernels in the recovery kernel partition (e.g. to try booting Meego, at the expense of no recovery mode, which is not a big problem.) But, in their infinite wisdom, Samsung decided that both normal and recovery modes would use the same kernel on the Tab. Rather than booting a completely separate kernel, the Tab boots the same kernel and the Android-specific init somehow recognises which mode was selected at boot time. It then proceeds to process either init.rc or recovery.rc.
Now this would give us an option of modifying the boot process, but the major problem is that while the Android init should support an exec command, this is not implemented in the version we have, and therefore even if we modify the recovery.rc file to try to start our own script to switch_root, etc., it won't work. The Android init used in the Tab is not stock Google code and there is no source available for the modifications.
Therefore I've renamed the Android init and replaced with it an init script which searches for Meego installations (btrfs partitions on the external SD card, or loop images) and if these are not found exec's the renamed Android init, which goes on its merry way and starts Android just like normal.
Getting Going
To add:
- how to backup existing Android install using heimdall
Grab the kernel source code from http://opensource.samsung.com/ Follow: Mobile > Mobile Phone > GT-P1000 > GT-P1000_OpenSource.zip. There is a new GT-P1000_OpenSource_Update1.zip but I've not tried that, please do tell if it works or works better ;)
- Link to kernel source (http://opensource.samsung.com/ search for "gt-p1000", select "GT-P1000_OpenSource.zip")
Extract the source, follow the instructions in the readme.txt to grab the cross-compiler and edit the relevant settings in the build_kernel.sh script.
- Link to cross-toolchain (http://www.codesourcery.com/public/gnu_toolchain/arm-none-linux-gnueabi/arm-2009q3-67-arm-none-linux-gnueabi-i686-pc-linux-gnu.tar.bz2)
Note that we use the same source and toolchain so that the PVR kernel modules will still work (as we're dual booting Android)
- patches to kernel defconfig (defconfig here: http://people.bath.ac.uk/enpsgp/Tab/kernel/)
- Patches to kernel to combine bootloader cmdline and compile-time cmdline (modified setup.c here, also needs some more patches to other files, add these: http://people.bath.ac.uk/enpsgp/Tab/kernel/)
Try compiling to see if it all works. It should do. If you get the following warning "WARNING: modpost: Found 13 section mismatch(es).", don't worry, that appears to be normal (!)
Note that we could try enabling kexec if we find that keeping compatibility with the Android kernel is too limiting and then kexec away to our less constrained kernel. Need to test this.
- link to zImage - for those who don't want to do any building (http://people.bath.ac.uk/enpsgp/Tab/kernel/zImage)
- link to scripts to extract and rebuild initramfs (http://people.bath.ac.uk/enpsgp/Tab/initramfs/)
- instructions for flashing kernel using heimdall (install heimdall: http://www.glassechidna.com.au/products/heimdall/ then: "heimdall flash --kernel zImage")
- link to kickstart file (http://people.bath.ac.uk/enpsgp/Tab/)
Add note about "extras" - modules are in initramfs, so just extract these and add to the image; wifi firmware and other files are in the Android install. We could extract these at runtime, but currently are setup for them to be pre-extracted and added to the Meego partition. Make some notes about location of these files and alternative methods of extracting at runtime.
- instructions for creating image and sticking that on a uSD card (same as N900 instructions)
(sudo mic-image-creator --run-mode=0 --cache=/home/simon/development/meego/build/mycachedir/ --format=raw --arch=armv7l --config=./meego-handset-armv7l-galaxy-tab-1.1.80.15.20110118.5.ks)
Setup notes
- Getting wifi up and running
- Using adb with Android to extract files from the live Android system (if required)
Useful things to look into
- How to decide whether to boot Android or Meego - work out how the Android init determines the boot mode (not a kernel command line param nor an argument passed to init, so presumably some /dev or /proc entry information?)
- Galaxy Tab keyboard scan codes - while the kb dock works, ctrl-c is non-functional, it does not have an escape key and there is no cursor displayed (makes vi editing fun ;))
NB
- Android will not start up unless you pass the standard bootloader cmdline arguments to the kernel, so if you want to add more arguments you need to either combine them or reproduce them at compile time. Either way you need a kernel patch as otherwise the bootloader cmdline overrides and replaces whatever you specified at compile-time.
- While adding console=tty0 to the kernel command line means you see the boot-time output, it prevents the Tab kb dock from functioning!
Ubuntu
Related Wiki Pages
MeeGo on ARM/Snapdragon (MSM/QSD)
Team members
- Steven Troughton-Smith / steventroughtonsmith - Nexus S & ??
- Simon Pickering / lardman - Galaxy Tab (Meego)
- lilstevie - Galaxy Tab (Ubuntu) & ??