memcpy.io

Git pull request fetching & searching

Robert Foss — Mon, 03 Jul 2023 19:32:00 +0200

Adam Jackson created the script add-gitlab-merge-requests.sh which is the basis of this workflow.

git pr

The idea is to provide local access to all of the PRs that exist upstream. This both provides a better general overview of which PRs that have been pulled into the branch you're working on, but also enables you to search the contents of all PRs.

This function automagically detects if your remote is hosted on GitHub or GitLab and makes the necessary adjustments to work on either platform.

[alias]
  mr = pr
  pr = "!f() { \
    REMOTES=$(git remote); \
    REMOTE=\"origin\"; \
    case \"$REMOTES\" in \
    *upstream*) \
      REMOTE=\"upstream\"; \
    ;; \
    esac; \
    \
    ORIGIN=${1:-${REMOTE}}; \
    URL=$(git remote get-url ${ORIGIN}); \
    \
    case \"$URL\" in \
    *gitlab*) \
      FORGE_EXT="mr" \
      FORGE_PATH="merge-requests" \
    ;; \
    *github*) \
      FORGE_EXT="pr" \
      FORGE_PATH="pull" \
    ;; \
    esac; \
    ORIGIN_NAME …

Setting up a Linux userspace graphics dev environment

Robert Foss — Wed, 26 Apr 2023 10:32:00 +0200

Set up alternative install location

These build instructions are based on the Wayland instructions from freedesktop.org.

You probably don't want to install experimental builds of software among the usual software of your operating system, so let's define a prefix for where to install our builds.

# Change ALT_LOCAL to any location you like
export WORK_DIR="/opt"
export PROJECT_NAME="feature_x"
export PROJECT_PATH="$WORK_DIR/$PROJECT_NAME"
export ALT_LOCAL="$PROJECT_PATH/local"
export LD_LIBRARY_PATH="$ALT_LOCAL/lib"
export PKG_CONFIG_PATH="$ALT_LOCAL/lib/pkgconfig/:$ALT_LOCAL/share/pkgconfig/"
export PATH="$ALT_LOCAL/bin:$PATH"
export ACLOCAL_PATH="$ALT_LOCAL/share/aclocal"
export ACLOCAL="aclocal -I $ACLOCAL_PATH"

# Needed by autotools
mkdir -p "$ALT_LOCAL/share/aclocal"

export XDG_RUNTIME_DIR="$ALT_LOCAL/xdg"
export XDG_CONFIG_HOME="$ALT_LOCAL/home"
export MESA_LOADER_DRIVER_OVERRIDE=zink

Installing dependencies

Start by installing the build dependencies of mesa, weston and …

Configuring Linux VLANs

Robert Foss — Wed, 20 Jul 2022 10:48:00 +0200

$ vlan
Device not provided

    vlan $DEV $VLAN $SUBNET

    vlan eth0 42 10.31.155.1/27

This is a achieved by pasting the below function into your .bashrc / .zshrc and issuing a source .bashrc or source .zshrc correspondingly.

function vlan {
    DEV=$1
    VLAN=$2
    ADDR=$3

    HELP="

    vlan \$DEV \$VLAN \$SUBNET

    vlan eth0 42 10.31.155.1/27
"

    if [ -z "$DEV" ]; then
        echo "Device not provided"
        echo "$HELP"
        return 1
    fi

    ip link | grep "${DEV}: " >/dev/null 2>&1
    if [ $? -ne 0 ]; then
        echo "\"$DEV\" is not a valid device"
        echo "$HELP"
        return 1
    fi

    if [ -z "$VLAN" ]; then
        echo "VLAN not provided"
        echo "$HELP"
        exit 1
    fi
    REGEX='^[0-9]+$'
    if ! [[ $VLAN =~ $REGEX ]] ; then
        echo "\"$VLAN\" is not a number" >&2; exit 1 …

Git Alias function syntax

Robert Foss — Thu, 04 Nov 2021 20:10:00 +0100

A basic example of the git alias function syntax looks like this.

[alias]
    shortcut = "!f() \
    {\
        echo Hello world!; \
    }; f"

This syntax defines a function f and then calls it. These aliases are executed in a sh shell, which means there's no access to Bash / Zsh specific functionality.

Every command is ended with a ; and each line ended with a \. This is easy enough to grok. But when we try to clean up the above snippet and add some quotes to "Hello world!", we hit this obtuse error message.

}; f: 1: Syntax error: end of file unexpected (expecting "}")

This syntax error is caused by quotes needing to be escaped. The reason for this comes down to how git tokenizes and executes these functions. If you're curious …

Applying mailing list patches with 'git b4'

Robert Foss — Mon, 08 Mar 2021 12:23:00 +0100

It was created by Konstantin Ryabitsev and has become a very frequently used tool for me.

It supports a lot of different ways for interacting with the Linux Kernel mailing lists. Of these the b4 am subcommand is what I primarily use. This subcommand downloads all of the patches belonging to a patch series and drops them into a .mbox file. But! It doesn't apply them to the repository we're currently in, and herein lies the itch that I would like to scratch.

The inspiration for this post is the script that @stellarhopper authored and @widawsky pointed out to me.

The Good, the Bad & the Ugly

After first publishing this post, people on the twittersphere suggested some alternative approaches, and it would seem that there …

Upstream camera support for Qualcomm platforms

Robert Foss — Tue, 23 Feb 2021 14:54:00 +0100

Linaro has been working together with Qualcomm to enable camera support on their platformssince 2017. The Open Source CAMSS driver was written to support the ISP IP-block with the same name that is present on Qualcomm SoCs coming from the smartphone space.

The first development board targeted by this work was the DragonBoard 410C, which was followed in 2018 by DragonBoard 820C support. Recently support for the Snapdragon 660 SoC was added to the driver, which will be part of the v5.11 Linux Kernel release. These SoCs all contain the CAMSS (Camera SubSystem) version of the ISP architecture.

Currently, support for the ISP found in the Snapdragon 845 SoC and the DragonBoard 845C is in the process of being upstreamed to the mailinglists. Having …

Speed up `git log --graph` 18x times

Robert Foss — Tue, 07 Apr 2020 15:06:00 +0200

$ time git lg
git lg  13.34s user 0.87s system 84% cpu 16.845 total

# True by default as of git v2.24
git config --global core.commitGraph true
git config --global gc.writeCommitGraph true

# Added in git v2.29, pre-compute file paths, so that git log commands
# that are scoped to files also benefit from this cache.
git commit-graph write --reachable --changed-paths

$ time git lg
git lg  0.72s user 0.14s system 74% cpu 1.154 total

This is a speed up of ~18x, compared to the older versions.

The way this works is that the commit-graph file stores the commit graph structure along with some extra metadata to speed up graph in the .git/objects/info directory.

Panfrost: Liberating ARM GPUs @ Linux Conf Au

Robert Foss — Wed, 15 Jan 2020 00:00:00 +0100

Downloads

If you're curious about the slides, you can download the PDF or the ODP.

Diagrams

Overview

Kernel

Userspace

Mesa overview

Mesa Gallium

Mesa Winsys

Mesa Compiler

License

All of the material you can find on this page is licensed under the MIT license, and you are free to use, modify and re-distribute these materials however you like.

Thanks

I would like to thank the wonderful organizers of Linux Conf Au for hosting the event. This was my first LCA, and I think it may be the best Linux conference out of all of them.

I would also like to thank the organizers for paying for my flights, without it I would not have been able to give this talk.

Panfrost the Open Source Arm GPU Driver @ ELC NA

Robert Foss — Sun, 22 Sep 2019 00:00:00 +0200

Downloads

If you're curious about the slides, you can download the PDF or the ODP.

Thanks

This post has been a part of work undertaken by my employer Collabora.

I would like to thank the wonderful organizers of ELC NA for hosting the event.

Status of the Embedded GPU Space @ ELC NA

Robert Foss — Sat, 21 Sep 2019 00:00:00 +0200

Downloads

If you're curious about the slides, you can download the PDF or the ODP.

Thanks

This post has been a part of work undertaken by my employer Collabora.

I would like to thank the wonderful organizers of ELC NA for hosting the event.

Running Android and Wayland on Embedded Devices

Robert Foss — Fri, 03 May 2019 10:39:00 +0200

A previous post introduced the SPURV Android compatibility layer for Wayland based Linux environment.
In this post we're going to dig into how you can run an Android application on the very common i.MX6 based Nitrogen6_MAX board from Boundary Devices.

Install dependencies

sudo apt install \
    apt-transport-https \
    bmap-tools \
    ca-certificates \
    curl \
    git \
    gnupg2 \
    repo \
    software-properties-common \
    u-boot-tools \
    qemu-kvm

Set up Docker container for building

# Install Docker
curl -fsSL https://download.docker.com/linux/debian/gpg | sudo apt-key add -
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/debian $(lsb_release -cs) stable"
sudo apt update
sudo apt install docker-ce

# Set up privileges for Docker
sudo usermod -aG docker ${USER}
su - ${USER}

# Fetch Docker image …

Running Android next to Wayland

Robert Foss — Mon, 01 Apr 2019 18:07:00 +0200

Running Android has some advantages compared to native Linux applications, for example with regard to the availability of applications and application developers.

For current non-Android systems, this work enables a path forward to running Android applications in the same graphical environment as traditional non-Android applications are run.

What is SPURV?

SPURV is our experimental containerized Android environment, and this is a quick overview of what it is.

It's aptly named after the first robotic fish since a common Android naming scheme is fish-themed names. Much like its spiritual ancestor Goldfish, the Android emulator.

Other Android Compatibility Layers

This means that Anbox which is LXC based, is different from SPURV in terms of how hardware is accessed. The hardware access that Anbox provides in indirect, and …

An Overview of the Panfrost driver

Robert Foss — Wed, 13 Mar 2019 16:25:00 +0100

The process of reverse engineering Arm GPUs has been going on for a long time, starting with Luc Verhaegens work on the low-end Mali 2/3/400 series of GPUs based on the Arm Utgard family of GPUs.
This driver has recently seen a lot new attention and is itself progressing quickly, which means it will likely be accepted into the kernel soon.
A piece of trivia is that this GPU architecture was what Arm received when they purchased the Norwegian GPU IP vendor Falanx Microsystems.

The Mali T and G-series of GPUs are based on the Midgard and Bifrost architectures respectively, both of which are quite different from the 2/3/400 series. However the T and G-series are somewhat similar at least when …

Status of the Embedded GPU Space @ Embedded World

Robert Foss — Wed, 27 Feb 2019 00:00:00 +0100

Downloads

If you're curious about the slides, you can download the PDF or the ODP and of course the whitepaper.

Thanks

This post has been a part of work undertaken by my employer Collabora.

I would like to thank the wonderful organizers of Embedded World for hosting a great event.

Running Docker privileged inside of LXC / LXD

Robert Foss — Mon, 03 Dec 2018 19:00:00 +0100

The architecture is a bit of container matroska, but what we're trying to achieve is running Docker privileged inside of a LXC container on a baremetal host.

Setup container on LXC Host

In order to give Docker in the guest privileges, the guest container itself has to be given privileges.

There is no simple switch for doing this in LXC unfortunately, but a few config options will do the trick.

lxc launch images:ubuntu/bionic container

lxc config set container security.nesting true
lxc config set container security.privileged true
cat <<EOT | lxc config set container raw.lxc -
lxc.cgroup.devices.allow = a
lxc.cap.drop =
EOT

lxc restart container

Setup docker on container

Just to verify that this works, start a privileged Docker container …

Android on Mainline Graphics @ All Systems Go

Robert Foss — Sat, 29 Sep 2018 00:00:00 +0200

Downloads

If you're curious about the slides, you can download the PDF or the ODP.

Thanks

This post has been a part of work undertaken by my employer Collabora.

I would like to thank the wonderful organizers of All Systems Go!, the @ASGConf for hosting a great event.

Status of the Open Source GPU Ecosystem @ OSSummit NA

Robert Foss — Fri, 31 Aug 2018 00:00:00 +0200

Downloads

If you're curious about the slides, you can download the PDF or the ODP.

Thanks

This post has been a part of work undertaken by my employer Collabora.

I would like to thank the wonderful organizers of OSSummit NA, the Linux Foundation for hosting a great event.

git reset upstream

Robert Foss — Fri, 24 Aug 2018 12:32:00 +0200

robertfoss@xps9570 ~/work/libdrm $ git ru
remote: Counting objects: 234, done.
remote: Compressing objects: 100% (233/233), done.
remote: Total 234 (delta 177), reused 0 (delta 0)
Receiving objects: 100% (234/234), 53.20 KiB | 939.00 KiB/s, done.
Resolving deltas: 100% (177/177), completed with 36 local objects.
From git://anongit.freedesktop.org/mesa/drm
   cb592ac8166e..bcb9d976cd91  master     -> upstream/master
 * [new tag]                   libdrm-2.4.93 -> libdrm-2.4.93
 * [new tag]                   libdrm-2.4.94 -> libdrm-2.4.94

The idea here is that we by issuing a single short command can fetch the latest master branch from the upstream repository of the codebase we're working on and set our local master branch to point to the most recent upstream/master one …

kms_swrast: A hardware-backed graphics driver

Robert Foss — Tue, 31 Jul 2018 09:14:00 +0200

Stack overview

Let's start with having a look at a high level overview of what the graphics stack looks like.

Before digging too much further into this, lets cover some terminology.

DRM - Direct Rendering Manager - is the Linux kernel graphics subsystem, which contains all of the graphics drivers and does all of the interfacing with hardware.
The DRM subsystem implements the KMS - kernel mode setting - API.

Mode setting is essentially configuring output settings like resolution for the displays that are being used. And doing it using the kernel means that userspace doesn't need access to setting these things directly.

The DRM subsystem talks to the hardware and Mesa is used by applications through the APIs it implements. APIs like OpenGL, OpenGL ES, Vulkan, etc. All …

Configuring QNAP LXC containers for VPNs using TUN

Robert Foss — Sun, 24 Jun 2018 22:16:00 +0200

Configuring the QNAP device

The first step is to SSH into your QNAP device using the admin account.

ssh admin@NAS_IP
cat >> /share/Container/container-station-data/lib/lxc/CONTAINER_NAME/config << EOF
lxc.cgroup.devices.allow = c 10:200 rwm
EOF

Configuring the container guest

The second step is open the QNAP web-ui, open the Container Station application and enter the console of your container.

sed -i '/exit 0/d' /etc/rc.local
cat >> /etc/rc.local << EOF
if ! [ -c /dev/net/tun ]; then
    mkdir -p /dev/net
    mknod -m 666 /dev/net/tun c 10 200
fi

exit 0
EOF

Lastly the container needs to be restarted, and then your VPN application should be able to access TUN devices and work normally.

Twistyplexing: A Charlieplexing variety

Robert Foss — Fri, 22 Jun 2018 12:26:00 +0200

The above layout has N = 7, yielding 42 LEDs.

Apart from the symmetry being visually pleasing compared to the normal row & column Charlieplexing layouts, it's relatively easy to spot errors in the schematic.

Avoiding lookup tables

The major advantage of twistyplexing is the ability to avoid lookup tables and replace them with some relatively straight forward arithmetic.

row = led_number / (N - 1)
column = led_number % (N - 1)
anode = (row + column + 1) % N

Of course the cathode still has to be controlled, but its pin id already defined by the row variable above.

Thanks

The Twistyplexing concept was created by Tom Yu, and defined in this blog post.

APA102 1515 LEDs

Robert Foss — Mon, 04 Jun 2018 22:26:00 +0200

The quiescent current of the APA102 2020 LEDs is about 0.7-1.0mA. Which is rather high for some usecases. But recently some new option have been made available.

The APA102 1515 and the APA104 1515, both of which come in a 1.5x1.5mm package. Additionally the APA104 1515 IC has a quiescent current of 0.3mA, which is good step in the right direction.

APA102 1515 datasheet

APA104 1515 datasheet

Unfortunately only the APA104 datasheet specifies quiescent current, so the quiescent current of the APA102 15155 is still an unknown.

Status of the Open Source Graphics Ecosystem @ OpenTechSummit

Robert Foss — Thu, 10 May 2018 00:00:00 +0200

Downloads

If you're curious about the slides, you can download the PDF or the OTP.

Thanks

This post has been a part of work undertaken by my employer Collabora.

I would like to thank the wonderful organizers of OpenTechSummit, specifically @hpdang and @mariobehling for hosting a great event.

Running Android on the Mainline Graphics Stack @ FossNorth

Robert Foss — Mon, 23 Apr 2018 00:00:00 +0200

Downloads

If you're curious about the slides, you can download the PDF or the OTP.

Thanks

This post has been a part of work undertaken by my employer Collabora.

I would like to thank the wonderful organizers of FossNorth, specifically @e8johan for hosting a great event.

Upstream Linux support for the new NXP i.MX 8M

Robert Foss — Fri, 13 Apr 2018 11:39:00 +0200

The i.MX6 platform has for the past few years enjoyed a large effort to add upstream support to Linux and surrounding projects. Now it is at the point where nothing is really missing any more. Improvements are still being made, to the graphics driver for i.MX 6, but functionally it is complete.

The i.MX8 is a different story. The newly introduced platform, with hardware still difficult to get access to, is seeing lots of work being done, but much still remains to be done.

That being said, initial support for the GPU, the Vivante GC7000, is in place and is able to successfully run Wayland/Weston, glmark, etc. This should also mean that running Android ontop of the currently not-quite-upstream stack is …

Status of the Embedded GPU Space @ Embedded Linux Conference NA

Robert Foss — Mon, 12 Mar 2018 00:00:00 +0100

A recording of the talk is available here.

Downloads

If you're curious about the slides, you can download the PDF or the OTP.

Thanks

This post has been a part of work undertaken by my employer Collabora.

I would like to thank the wonderful organizers of Embedded Linux Conference NA, for hosting a great event.

APA102 LED Current Usage

Robert Foss — Tue, 20 Feb 2018 22:26:00 +0100

What we're seeing here is a the LED being fully off (albeit with floating clock and data inputs), drawing somewhere between 0.7-1 mA.

I was quite surprised to see such a high quiescent current.

For the APA102 2020 which has a 20x20mm footprint this is somewhat disappointing, not because it is worse than the normal 50x50 APA102 variants, but rather because the small footprint begs for the IC to be used in wearables and other power consumption sensitive applications.

Setup

So this is the very simple setup I was using. It's nothing fancy; a multimeter set to the mA range, connected between the power supply and the APA102 breakout board I happened to have laying around.

Virtualizing GPU Access

Robert Foss — Fri, 09 Feb 2018 11:17:00 +0100

For the past few years a clear trend of containerization of applications and services has emerged. Having processes containerized is beneficial in a number of ways. It both improves portability and strengthens security, and if done properly the performance penalty can be low.

In order to further improve security containers are commonly run in virtualized environments. This provides some new challenges in terms of supporting the accelerated graphics usecase.

OpenGL ES implementation

Currently Collabora and Google are implementing OpenGL ES 2.0 support. OpenGL ES 2.0 is the lowest common denominator for many mobile platforms and as such is a requirement for Virgil3D to be viable on the those platforms.

That is is the motivation for making Virgil3D work on OpenGL ES hosts.

How …

Android on Mainline Graphics @ FOSDEM

Robert Foss — Sun, 04 Feb 2018 00:00:00 +0100

A recording of the talk can be found here.

Downloads

If you're curious about the slides, you can download the PDF or the OTP.

Thanks

This post has been a part of work undertaken by my employer Collabora.

I would like to thank the wonderful organizers and volunteers of FOSDEM, for hosting a great community event.

Building ChromiumOS for Qemu

Robert Foss — Tue, 28 Nov 2017 11:32:00 +0100

So let's start off by covering how ChromiumOS relates to ChromeOS. The ChromiumOS project is essentially ChromeOS minus branding and some packages for things like the media digital restrictions management.

But on the whole, almost everything is there, and the pieces that aren't, you don't need.

ChromiumOS

Depot tools

In order to check out ChromiumOS and other large Google projects, you'll need depot tools.

git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git
export PATH=$PATH:$(PWD)/depot_tools

Maybe you'd want to add the PATH export to your .bashrc.

Building ChromiumOS

mkdir chromiumos
cd chromiumos
repo init -u https://chromium.googlesource.com/chromiumos/manifest.git --repo-url https://chromium.googlesource.com/external/repo.git [-g minilayout]
repo sync -j75
cros_sdk
export BOARD=amd64-generic …

Fixing bluetooth on the XPS 15 9550 on Ubuntu

Robert Foss — Sat, 28 Oct 2017 00:00:00 +0200

Why doesn't this work automatically?

The firmware blob that is needed by Broadcom devices is not supplied by default, and it has to be supplied manually.

How To

Download BCM-0a5c-6410.hcd and copy it into /lib/firmware/brcm/ and then reboot your device.

wget https://memcpy.io/files/2017-10-28/BCM-0a5c-6410.hcd
sudo cp BCM-0a5c-6410.hcd /lib/firmware/brcm/
sudo chmod 0644 /lib/firmware/brcm/BCM-0a5c-6410.hcd
sudo reboot

Android on Mainline Graphics @ Embedded Linux Conference EU

Robert Foss — Wed, 25 Oct 2017 00:00:00 +0200

A recording of the talk can be found here.

Downloads

If you're curious about the slides, you can download the PDF or the OTP.

Thanks

This post has been a part of work undertaken by my employer Collabora.

I would like to thank the wonderful organizers of Embedded Linux Conference EU, for hosting a great community event.

drm_hwcomposer: A brief update @ XDC 20117

Robert Foss — Fri, 22 Sep 2017 00:00:00 +0200

Downloads

If you're curios about the slides, you can download the PDF or the OTP.

Thanks

This post has been a part of work undertaken by my employer Collabora.

I would like to thank the wonderful organizers of XDC, and Google for hosting a great community event.

Android on Mainline Graphics @ Open Source Summit NA

Robert Foss — Mon, 11 Sep 2017 00:00:00 +0200

Downloads

If you're curious about the slides, you can download the PDF or the OTP.

Thanks

This post has been a part of work undertaken by my employer Collabora.

I would like to thank the wonderful organizers of Open Source Summit NA, for hosting a great community event.

Android on Mainline Graphics @ GDG Berlin Android

Robert Foss — Fri, 01 Sep 2017 00:00:00 +0200

I would like to thank the wonderful organizers, GDG Berlin Android, for hosting a great community event.

Downloads

If you're curios about the slides, you can download the PDF or the OTP.

Android: NXP i.MX6 on Etnaviv Update

Robert Foss — Fri, 21 Jul 2017 00:00:00 +0200

Since the last post a lot work has gone into upstreaming and stabilizing the etnaviv on Android ecosystem. This has involved Android, kernel and Mesa changes. Many of which are available upstream now. A How-To for getting you up and running on an iMX6 dev board is available here.

Improvements

Modifiers support

Modifiers support has been accepted into Mesa, GBM and gbm_gralloc. Modifiers were mentioned in a previous post.

Etnaviv driver support for Android

Patches enabling the etnaviv Mesa driver being built for Android have now landed upstream.

Stability on Android

A number for small stability issues present while running Android on i.MX6 hardware have now been fixed, and the platform is now relatively stable.

Performance diagnostics

We have a decent understanding that the …

GALLIUM_HUD: Debug Mesa Graphics Performance

Robert Foss — Wed, 28 Jun 2017 00:00:00 +0200

GALLIUM_HUD

GALLIUM_HUD is a feature that adds performance graphs to applications that describe various aspects like FPS, CPU usage, etc in realtime.

It is enabled using an environment variable, GALLIUM_HUD, that can be set for GL/EGL/etc applications. It only works for Mesa drivers that are Gallium based, which means that the most drivers (with the notable exception of some Intel drivers) support GALLIUM_HUD.

See GALLIUM_HUD options:

export GALLIUM_HUD=help
glxgears

Android

If you're building Android, you can supply system-wide environment values by doing an export in the init.rc file of the device you are using, like this.

# Go to android source code checkout
cd android

# Add export to init.rc (linaro/generic is the device I use)
nano device/linaro/generic/init …

Android: NXP i.MX6 Buffer Modifier Support

Robert Foss — Fri, 02 Jun 2017 00:00:00 +0200

With modifier support added to Mesa and gbm_gralloc, it is now possible to boot Android on iMX6 platforms using no proprietary blobs at all. This makes iMX6 one of the very few embedded SOCs that needs no blobs at all to run a full graphics stack.

Not only is that a great win for Open Source in general, but it also makes the iMX6 more attractive as a platform. A further positive point is that this lays the groundwork for the iMX8 platform, and supporting it will come much easier.

What are modifiers used for?

Modifiers are used to represent different properties of buffers. These properties can cover a range of different information about a buffer, for example compression and tiling.

For the case of …

Android: Getting up and running on the iMX6

Robert Foss — Thu, 27 Apr 2017 00:00:00 +0200

Since the hardware very much matters this is going to be divided into a few parts, the common steps and the hardware specific ones.

This post is a bit of a living document and will be changed over time, and if you have any questions about it, please reach out through email (robert.foss at collabora.com) or irc (tomeu or robertfoss on #dri-devel on freenode).

Changelog:
2017-04-27: build_android.sh, setup_sdcard.sh: Added -b [device] support to build_android.sh and setup_sdcard.sh
2017-05-02: build_android.sh: Don't write to SD-card without -b option
2017-05-04: Switch git repo urls to shared repository
2017-05-09: Add compiler installation to apt-get
2017-05-09: Re-ordered some instructions
2017 …

Android: Changing the bootanimation

Robert Foss — Thu, 20 Apr 2017 00:00:00 +0200

There exists official documentation for how to create a custom boot animation, but unfortunately it is lacking in actual examples.

So this guide is a bit more hands on.

Structure of bootanimation.zip

Without covering too much of the same gound as the documentation, let's have a quick look at what is in a simple bootanimation.zip.

$ ls -la bootanimation
total 28
drwxr-xr-x 4 hottuna hottuna 4096 Apr 19 22:39 .
drwxr-xr-x 8 hottuna hottuna 4096 Apr 19 22:39 ..
-rw-r--r-- 1 hottuna hottuna   92 Apr 19 15:21 desc.txt
drwxr-xr-x 2 hottuna hottuna 4096 Apr 19 12:44 part0
drwxr-xr-x 2 hottuna hottuna 4096 Apr 19 12:45 part1

$ cat bootanimation/desc.txt …

Audio editing images

Robert Foss — Sun, 09 Apr 2017 21:35:00 +0200

Audio Shop is a simple script that I cobbled together that gets you started with mangling image data as if it was audio data.

The script wraps 3 individually excellent tools; ffmpeg, ImageMagick and SoX.

The way it works is by first converting an image to a raw format like rgb or yuv. This is done to prevent the audio editor from destroying the structure of (relatively) complex formats like jpg, png or gif.

If converting to a raw format is the first step, the second step is importing the raw image data into the audio editor. To do this in way you can expect good results from, the raw format should use a bit-depth that your image editor can use. For example RGB, where …

Android: Enabling mainline graphics

Robert Foss — Tue, 28 Mar 2017 15:18:00 +0200

The HWC (Hardware Composer) API is used by SurfaceFlinger for compositing layers to the screen. The HWC abstracts objects such as overlays and 2D blitters and helps offload some work that would normally be done with OpenGL. SurfaceFlinger on the other hand accepts buffers from multiple sources, composites them, and sends them to the display.

The above graphic depicts the traditional Android graphics stack.

This is where drm_hwcomposer comes into play. Since the mainline kernel graphics stack doesn't offer the HWC API, drm_hwcomposer is introduced to interface with the mainline graphics stack through mesa and libdrm. Before this work drm_hwcomposer only offered the HWC1 API. Since Android 7.0 version 2 of the HWC API is used by SurfaceFlinger. HWC2 differs in a few ways …

Removing the Chromebook Write-Protect screw

Robert Foss — Mon, 27 Feb 2017 16:55:00 +0100

This post will look specifically at removing the WP screw from a Chell (HP Chromebook 13 G1) device, and verifying that it has been successfully removed.

To actually flash firmware to Chromebook machines, a device called a Servo is needed. While these devices aren't available publicly, they can be produced freely or possibly requested from Google if you are contributing code to the ChromiumOS project.

Removing the Write-Protect screw

So this is what the WP screw looks like on a Chell Chromebook. This may or may not be what you will find in other devices. But if you take a close look, you will notice that the copper pad that the the screw attaches against is split into parts that are bridged by a screw …

Precompiling APK files during Android AOSP build

Robert Foss — Wed, 22 Feb 2017 16:55:00 +0100

Enable precompilation

cd /opt/aosp_checkout/

find . -name BoardConfig.mk
./device/huawei/angler/BoardConfig.mk
./device/generic/mini-emulator-x86/BoardConfig.mk
./device/generic/arm64/BoardConfig.mk
./device/generic/mini-emulator-x86_64/BoardConfig.mk
./device/generic/mini-emulator-armv7-a-neon/BoardConfig.mk
./device/generic/mips/BoardConfig.mk
./device/generic/mips64/BoardConfig.mk
./device/generic/x86_64/BoardConfig.mk
./device/generic/mini-emulator-arm64/BoardConfig.mk
./device/generic/mini-emulator-mips/BoardConfig.mk
./device/generic/x86/BoardConfig.mk
./device/generic/armv7-a-neon/BoardConfig.mk
./device/generic/mini-emulator-mips64/BoardConfig.mk
./device/lge/bullhead/BoardConfig.mk
./device/linaro/generic/linaro_x86_64_only/BoardConfig.mk
./device/linaro/generic/linaro_arm64/BoardConfig.mk
./device/linaro/generic/linaro_arm64_only/BoardConfig.mk
./device/linaro/generic/linaro_x86_64/BoardConfig.mk
./device/linaro/generic/BoardConfig.mk
./device …

Setting up a ChromiumOS dev environment

Robert Foss — Thu, 16 Feb 2017 10:31:00 +0100

Set up environment

export DEV_DIR="/opt"
mkdir -p $DEV_DIR
export CHROMIUM_DIR="$DEV_DIR/chromiumos"
mkdir -p $CHROMIUM_DIR
export PATH="$DEV_DIR/depot_tools:$PATH"

# The BOARD variable used here is specific for the Chromebook that is
# being targeted, a more generic target like "amd64-generic" could
# be more useful for you needs.
export BOARD=chell

# The USB_DEVICE variable refers to the USB device that will be used
# for flashing ChromiumOS onto a Chromebook.
# Make sure that this device does not contain anything important!
export USB_DEVICE="/dev/sda"

Install dependencies

sudo apt install git-core gitk git-gui subversion curl
cd $DEV_DIR
git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git

Get ChromiumOS source

cd ${CHROMIUM_DIR}
repo init -u https://chromium.googlesource.com/chromiumos/manifest.git
repo sync -j25 …

Running an Android Unit Test

Robert Foss — Wed, 07 Dec 2016 20:23:00 +0100

A similar approach can be used for any Android module.

cd aosp
bash
source build/envsetup.sh && \
lunch linaro_arm64-userdebug && \
mmm system/core/libsync/tests && \
adb root && \
adb remount && \
adb sync && \
adb shell /data/nativetest64/sync-unit-tests/sync-unit-tests

XDC 2016

Robert Foss — Fri, 23 Sep 2016 20:20:00 +0200

XDC 2016 was hosted in Helsinki at Haaga-Helia. The full program was filmed and is archived here.

[Slides] FastUIDraw - High Performance 2D renderer for GPUs

Kevin Rogovin gave an excellent talk about FastUIDraw, which is a highly optimiser 2d renderer for GPUs.

By agressively targetting GPUs only and limiting the feature set to what is required by a browser FastUIDraw performs >9.3x faster than Cairo-CPU and >4.8x times the previous GPU state of the art SKIA-GL.

Hopefully FastUIDraw can be incorporated into upstream of ChromiumOS and Android.

[Slides] 2D Performance

Martin Perez gave a talk about 2D performance and power consumption of the Xserver.

The xf86-video-intel driver showed quite mixed performance numbers of 1.51-32.6x times the CPU performance. The FPS/Watt …

Building Android for Qemu with Mesa and Virgil3D

Robert Foss — Tue, 30 Aug 2016 15:22:00 +0200

Developing Linux for Android on Qemu allows you to do some things that are not necessarily possible using the stock emulator. For my purposes I need access to a GPU and be able to modify the driver, which is where Virgilrenderer and Qemu comes in handy.

The guide below helps you compile Android and run it on top of Qemu with Mesa/Virgilrenderer supplying a virtual GPU. Because of this, the following guide is aimed at Linux hosts.

This guide is based on Rob Herrings fantastic guide, but has been slightly streamlined and had physical hardware support stripped out.

Install dependencies

These dependencies were available on Ubuntu 16.04, some alternative packages might be needed for other distributions.

sudo apt install autoconf gcc-aarch64-linux …

Ethernet device stress testing

Robert Foss — Thu, 25 Aug 2016 13:05:00 +0200

During testing of power management patches for usb ethernet dongles, a script was needed to stress test connecting/disconnecting/reconnecting these devices.

Luckily a script like that already exists as a part of the chromiumos project, and can be found here.

That script does however not run standalone and requires a remote device (chromebook) to execute on. So I took the liberty of changing it to support local testing. The modified version can be found here.

This might come in handy for someone, if not, the script will at least be archived on this site.

Example

$ sudo pip2.7 install autotest
$ ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1
    link/loopback 00:00:00 …

Linux kernel development shell scripts

Robert Foss — Tue, 26 Jul 2016 10:32:00 +0200

While upstreaming kernel patches scripts/checkpatch.pl and scripts/get_maintainer.pl often come in handy. But to me the interface they provide is slightly bulky and rely on using patch files instead of git commits, which to me is a bit inconvenient.

These scripts are all meant to be included in .bashrc or .zshrc

scripts/checkpatch.pl helper

#!/bin/bash
function checkpatch {
  if [ -z ${1+x} ]; then
    exec git diff | scripts/checkpatch.pl --no-signoff -q -
  elif [[ $1 == *"cache"* ]]; then
    exec git diff --cached | scripts/checkpatch.pl --no-signoff -q -
  else
    NUM_COMMITS=$1
    exec git diff HEAD~$NUM_COMMITS..HEAD | scripts/checkpatch.pl --no-signoff -q -
  fi
}

The checkpatch script simply wraps the patch creation process and allows …

Running Weston on a Raspbian

Robert Foss — Fri, 03 Jun 2016 10:32:00 +0200

Progress in the VC4 graphics camp and the Wayland camp now enables us to run Weston on top of the drm backend for VC4 platforms. Previously software acceleration using pixman was needed, but this is no longer the case.

Additionally the rpi backend for weston is now being removed since it has been obsoleted by the improved drm layer.

Let's explore running hardware accelerated Weston on the Raspberry Pi.

Building Linux kernel

A comprehensive guide for building a recent Linux kernel for Raspberry Pi boards has been written by the Raspberry Pi foundation and is available here.

As of this writing the guide helps you build a v4.4 kernel which is good enough for our purposes.

Set up alternative install location

These build instructions …

Coverpage template

Robert Foss — Sun, 27 Mar 2016 00:34:00 +0100

Coverpage is a single-page landing page built to showcase an idea or a product. To allow interested parties to get notified of updates, the template has mailchimp subscription integration.

A live version of the site can be found at coverpage.memcpy.io.

Sources

git clone https://github.com/robertfoss/coverpage.git

GitHub hosting

This template was built with the explicit intention of having it be hosted at GitHub in a gh-pages branch. Therefore it includes a Makefile for pushing copy of the current design to a gh-pages branch.

ESP8266 APA102 Bulb

Robert Foss — Sun, 07 Feb 2016 22:46:00 +0100

The product of this project is a WiFi connected LED bulb. Every LED on this bulb is individually programmable over the WiFi, by simply sending UDP packets to the bulb.

Software and hardware sources

git clone https://github.com/robertfoss/esp8266_apa102_bulb.git

This project consists of 3 parts: the software running on the led bulb, the software running on some host computer and the hardware.

Firmware

The firmare is based on the NodeMCU firwmare for the ESP8266. It's running the APA102 LED driver and the enduser setup module, which I've written about previously.

Additionally it's running 3 lua scripts that deal with different aspects.

There's init.lua which makes sure we're connected to a WiFi.

udp_listener.lua receives UDP packets and then sends forwards that …

WS2812 LED Matrix

Robert Foss — Mon, 12 Oct 2015 16:51:00 +0200

The LED Matrix is constructed out of a WS2812B 8x8 panel, a 3D printed case, an ESP8266, a LiPo battery and some software.

Code

git clone https://github.com/robertfoss/esp8266_ws2812_matrix.git

The software is divided into two parts. The receiving end is run on the ESP8266 that has been flashed with NodeMCU and is a simple lua script that receives UDP packets and forwards them to the excellent WS2812 module created by the the equally excellent Konrad Beckmann.

The second part is run on a host pc. It's a simple python script that generates a framebuffer from a sinusoidal animation and transmits it over UDP to the IP of the ESP8266. This relies on the host pc being able to connect to the ESP8266 …

WS2812 Welding Goggles

Robert Foss — Sun, 11 Oct 2015 13:16:00 +0200

The goggles were built using an AtTiny85 module and a WS2812B strip and some bits and bobs that were laying around. A more complete BOM can be found below.

Code

git clone https://github.com/robertfoss/digispark_ws2812_waves.git

The animation is built ontop of the excellent light_ws2812 library. It supports the AtTiny85 better than other competing libraries like FastLED.

The animation is built around an non-float sin function and a HSV function that generates the actual colors.

Video

Your browser does not support the video tag.

Bill of materials

6€ Weldorado STROOF DIN4 Welding Goggles
2$ Digispark
23$ WS2812B Strip 144 LEDs/m - Only about a 5th of the length needed.
2x$4 LiPo 3.7V 300mAh
$3 LiPo USB Charger
$6 Battery connector cable …

User friendly setup of ESP8266 gadgets

Robert Foss — Thu, 30 Jul 2015 15:10:00 +0200

The ESP8266 lacks a simple end-user compatible way to be configured with the login details of the local WiFi. Running the ESP8266 in a 'captive portal' mode where every http request is hijacked and replaced with form allows the end user to submit the credentials of the local WiFi hotspot by simply connecting to an ESP8266 hosted access point.

esp8266_nodemcu_wifi_setup is designed to provide a simple interface for users to configure their ESP8266/NodeMCU based devices through.

Start ESP.
Connect to the "SetupGadget" WiFi through your internet enabled thing of choice.
Submit credentials of your local WiFi.
The ESP reboots and connects to your local WiFi.

What is this magic! How could a mere mortal like me summon features like this?!

Let me tell you …

Building NodeMCU for the ESP8266

Robert Foss — Thu, 14 May 2015 11:31:00 +0200

This is a simple step-by-step guide to building and flashing NodeMCU for the ESP8266.

Build ESP8266 SDK

sudo apt-get install make unrar autoconf automake libtool gcc g++ gperf flex bison texinfo gawk ncurses-dev libexpat-dev python sed
cd /opt
git clone https://github.com/pfalcon/esp-open-sdk.git
cd esp-open-sdk
git submodule sync
git submodule update
make
export PATH=/opt/esp-open-sdk/xtensa-lx106-elf/bin:$PATH

Build NodeMCU

git clone https://github.com/nodemcu/nodemcu-firmware.git
cd nodemcu-firmware
# Switch to dev branch, since it's the most up to date
git checkout --track origin/dev
# Make INTEGER version, since it uses less memory/space
make EXTRA_CCFLAGS="-DLUA_NUMBER_INTEGRAL"

Flash NodeMCU

COMPORT=/dev/ttyUSB0 make flash