Status of the Ubuntu port to the AC100/Dynabook Tegra based netbook

Ubuntu on AC100 is currently an official demonstration of the Ubuntu ARM port and works fairly well. This page collects information necessary to get a working Ubuntu 11.10 port on the AC100.

Installing Ubuntu 11.10 on the AC100

Installation requirements

• Mini-usb cable
• Host computer with linux (virtual or physical)
• Usb-stick or sd-card (min. 1GB)
• About 1-2h of your life (depending on the download-time)

Files to download

For the installation, you will need to download these things:

Oneiric Installer

There are two AC100 related files in the oneiric release directory:

• Bootimage

• Preinstalled rootfs

Get them both and make sure that the md5sum corresponds after the download.

nvflash

The bootimage needs to be flashed via a mini-USB cable and using the nvflash tool.
This image when booted will set up the internal storage using a tarball provided on a USB stick or SD card.

• Install nvflash using a debian package
  

The link contains instructions on how to easily install nvflash to your current debian-based linux-distro.

Installation

The installation is done in two phases:

Flashing the bootimage

• Make sure the battery is full on the AC100, or that the charger is connected.
• Shut down the AC100.
• Connect the mini-usb from the AC100 to your host computer. The mini-usb socket is on the right side, left of the power-connector.
• Put netbook in recovery mode by booting with CTRL and ESC buttons held down. The screen stays off while the power led lights up.
• On your host computer, open a terminal and run:

  nvflash --bl /usr/lib/nvflash/fastboot.bin --download 6 /path/to/ubuntu-11.10-preinstalled-desktop-armel+ac100.bootimg
  NOTE: the path and name of fastboot.bin might vary, the guide uses version from http://share.grandou.net

• Once nvflash is finished and prints out a message stating success, turn off the AC100 by pressing on the power button for several seconds.

Installing the preinstalled rootfs

• Copy ubuntu-11.10-preinstalled-desktop-armel+ac100.tar.gz to a USB stick as a regular file on the first partition. NOTE: DO NOT UNPACK OR DD THE TARBALL, JUST COPY! Make sure the md5sum is alright after copying to the media.

• Reboot with the USB stick inserted and follow the simple instructions. Overall it does one reboot and in total can take about 20-30 minutes.

Notes on installation

• To do an install to external media the installer also supports installing from USB key to SD card (not the other way around !). To do such an install put the tarball on the USB key and make sure an empty SD card is in the slot before starting the installation, the installer will offer you to install to a partition on mmcblk1 (SD card) instead of mmcblk0 (internal eMMC drive).
• Although the installer offers the possibility to encrypt your home, this does not work. See the end of this document for instructions on enabling encryption.
• By default, only audio through headphones is enabled after the install, and will stop working after suspend/resume. See the end of this document for instructions on enabling audio through speakers.

• The package cache may be stuck for a while after the installation. Updates will start appearing after a day or so. It may be possible to speed this up by running sudo apt-get check.

A Note About Fragmentation

The effort the bring hardware support has always been fragmented. We are thankful for phh who did the initial bringup of a working linux kernel on the ac100 and made Linux4Tegra work on the older root filesystems ogra who built all Ubuntu root filesystems and the official oneiric images, marvin24 who has put effort in porting the Chrome OS kernel to the AC100, and the many others who were involved.

The downside of this fragmentation is that documentation is fragmented too. The goal of this wiki is to provide good quality information for the latest and most promising effort.

Wiki maintainers: don't reference the old "wetpaint" wiki. It is virtually unmaintained and will cause confusion. Information about the inner workings of the device and drivers must go here: http://ac100.grandou.net/

Hardware

The AC100 is an nVidia Tegra2 based device which has Android 2.1 as factory default. It has dual ARM Cortex-A9 cores at 1 GHz and nVidia GPU technology on its System On Chip (SoC). Some models come with 3G modems and the eMMC flash storage comes in various sizes.

Strengths

• Very slim and light
• Long battery life
• HDMI out

Weaknesses

• Slow eMMC storage (not an SSD)
• Only 512MB of RAM
• No VGA out (must use a displaylink device for most projectors)

Features known to work on Ubuntu: webcam, touchpad, 3G modem, WiFi, OpenGL ES (proprietary), indicator LEDs, card reader, audio, suspend/resume, HDMI out (with the proprietary nvidia drivers)

Incomplete support: video acceleration.

For details and a list of models, see http://ac100.grandou.net/models

Boot loader

The current first stage bootloader is Android Fastboot which uses the kernel and initramfs images found on partition 6 of the device. The partition can be written via the mini-USB port from another computer using the closed source nvflash utility from nvidia or opensource putusb, or updated from an already running system. The boot partition can be handled using the abootimg tool.

The ac100 PPA has a kernel that reads the (nvidia-proprietary format) main partition table, so kernel upgrades are possible. The flash-kernel package in the PPA takes care of this (note that all packages from the PPA are integrated in the oneiric images linked above, in oneiric the PPA will only be used for post-release updates of single packages).

U-Boot

The default boot loader is inflexible, and there is interest in adding U-Boot as a second stage boot loader. There are Tegra based U-Boot using devices but there's no working AC100 image yet that can handle the eMMC or the screen to be actually useful for a wider audience.

Kernel development

As of early September 2011 a 2.6.38-chromeos kernel fork is used in Ubuntu and included in the Oneiric archives. It supports suspend/resume and sound from the headphones is working, speakers do not yet.

Work is done to upstream AC100 support patches in 3.x kernels so we can use mainline eventually.

The kernel tree the Ubuntu package is based on is at https://gitorious.org/~marvin24/ac100/marvin24s-kernel

Known issues and tips for Ubuntu 11.10 and 12.04

Graphics

Latest Linux4Tegra SDK from Nvidia is 12alpha1 for kernel 2.6.38. This is not installed by default.

WebGL

Chromium browser v 13 from the Oneiric Ocelot archive works with some WebGL demos if passed --use-gl=egl --ignore-gpu-blacklist at the command line.

http://www.khronos.org/webgl/wiki/Demo_Repository

GLES demos

The native visual ID for all EGL fbconfigs seems to be returned as 0. This is bug acknowledged by NVidia.

eglGetConfigAttrib(ed, &config, EGL_NATIVE_VISUAL_ID, &id); //id = 0

so most GLES apps will not work as there appears to be no visual with that ID.

Example of change needed in es2tri.c and eglut_x11.c from the mesa-utils-extra package

- visInfo = XGetVisualInfo(x_dpy, VisualIDMask, &visTemplate, &num_visuals); + visInfo = XGetVisualInfo(x_dpy, VisualNoMask, &visTemplate, &num_visuals);

Some vertex and fragment shaders may show compile errors with the L4T driver. Mercifully, the error messages are usually informative enough to help fix the problem.

Example of change needed in es2gears.c from the mesa-utils-extra package

  static const char fragment_shader[] =
+ "#ifdef GL_ES\n"
+ "precision mediump float\n;"
+ "#endif\n"
  "varying vec4 Color;\n"

It is vital that none of the Mesa library equivalents of libGLESv2.so, libGLESv1_CM.so or libEGL.so are loaded by your target application at runtime. Doing this will make the application fail around the context creation step.

A good way to check is to run:

ldd ./name_of_gles_app | grep GL

All entries on the list should point to files in /usr/lib/nvidia-tegra.

Screen depth

By default, the L4T driver provides a 32-bit screen depth, which should be fully compatible with GLES.

It may be possible to improve performance by setting a depth of 16-bit in /etc/X11/xorg.conf

Section "Screen"
 Identifier "<myscreen>"
 Device "Tegra"
 DefaultDepth 16
EndSection

Installing Adobe Flash

An Adobe Flash installer is not yet available in the official repositories although there is a version that works on the AC100. You can install it for all users:

sudo wget -O /usr/lib/mozilla/plugins/libflashplayer.so http://kotelett.no/ac100/phh/Android2.2/libflashplayer.so

Enabling ZRAM compressed swap

• This (should) happen automatically with the 12.04 (precise) images (but doesn't atm because zram support is missing from the kernel), only use this method on oneiric (11.10)

Since the AC100 only has 512Mb of RAM some applications will complain when the RAM gets full. The default 11.10 install does not have any swap or compressed RAM enabled. Compressed RAM may not be completely stable, but is much faster than the internal MMC. You can, however, enable either or both, and by these instructions ZRAM will have higher priority.

ZRAM is a compressed ramdisk that can be enabled when using the latest Linux kernels. In effect, the ZRAM ramdisk can be used as a way to fit more applications into the AC100 RAM. ZRAM disks are also quicker to use than to enable a swap device on flash.

The file zramswap.conf can be placed in /etc/init/ and will make Upstart configure and enable ZRAM on bootup:

sudo wget -O /etc/init/zramswap.conf 'https://wiki.ubuntu.com/ARM/TEGRA/AC100?action=AttachFile&do=get&target=zramswap.conf'

Making use of extra partitions

The default installation leaves some partitions unused. Typically these are the partitions 3 (300MB), 4 (400MB), 5 (2MB) and 6 (1200MB) from the default partition layout of the Android 2.2 system from Toshiba. Before doing anything, verify that these are indeed the partition numbers on your system as they may be vary from model to model and may change with newer kernels. To find out, first see which partitions are currently in use and their size:

sudo mount
sudo df -h

The root (currently mounted as /, typically partition 7) and boot (is not mountable and begins with some 'ANDROID' and 'Ubuntu Boot Img' if you head it, typically partition 2) should not be touched. Unmount the other partitions you wish to use (replace X with the partition number):

sudo umount /dev/mmcblk0pX

Emptying the partitions

To simply prevent them showing up in file managers or unity, you can overwrite them with zeroes (replace X with the partition number):

sudo dd if=/dev/zero of=/dev/mmcblk0pX

Using the partitions as swap

• Attention: MMC devices have a limited life cycle for writing to them, using such devices for swap space where you have enormous amounts of constant writes will significantly shorten the life cycle of these devices. The built in MMC is not replaceable, use the method below at your own risk.

To use them as swap create a swap system on them (replace X with the partition number):

sudo mkswap /dev/mmcblk0pX

Then add the UUID given in the output of the previous command to fstab to automatically be used at boot (replace Y with the UUID):

sudo bash -c "echo 'UUID=Y none swap sw 0 0' >> /etc/fstab"
sudo swapon -a

Reformatting the partitions for storage

To use an extra partition for storage that can be mounted in file managers, create an ext4 file system on the partition (replace X with the partition number):

sudo mkfs.ext4 /dev/mmcblk0pX

If you want it to be automatically mounted at boot, continue by finding out its UUID (replace X with the partition number):

sudo blkid -o value -s UUID /dev/mmcblk0pX

Then add the UUID given in the output of the previous command to fstab to automatically be used at boot (replace Y with the UUID and Z with the mount point):

sudo bash -c "echo 'UUID=Y Z ext4 defaults  0 0' >> /etc/fstab"

Sound from speakers

After installation, upgrade all packages and make sure that the kernel 1001 was installed and reboot into it. Now you can enable audio through the speakers:

sudo amixer set 'SpeakerOut Mux',0 "Speaker Mix"
sudo amixer set 'Line',0 unmute
sudo -H alsactl store

NOTE: The unmute command needs to be verified. You can use alsamixer to unmute all speakers. NOTE:!! You still need to fiddle a bit with alsamixer settings to get sound to work (Right/Left Headphone Mux + SpeakerOut (N) Mux)

Encryption

Only put here links that are still relevant for present and future development and do not lead to unnecessary work and confusion. In particular, try to avoid the wetpaint wiki.

• Detailed info, useful for developers and power users but not specific to ubuntu: http://ac100.grandou.net/

• IRC-logs for #ac100 @ irc.freenode.net can be found here: http://ac100.tunk.org/logs/

CategoryHardware