17 Jan 2021

feedPlanet Maemo

Ubuntu Touch porting notes for the Redmi Note 7 Pro

In case you have a sense of deja-vu when reading this post, it's because indeed this is not the first time I try porting a device to Ubuntu Touch. The previous attempt, however, was with another phone model (and manufacturer), and did not have a happy ending. This time it went better, although the real ending is still far away; but at least I have something to celebrate.

The phone

I made myself a Christmas present and bought a Xiaomi Redmi Note 7 Pro, a dual-SIM phone from 2019 with 6GB of RAM and 128GB of flash storage. To be totally honest, I bought it by mistake: the phone I really wanted to buy is the Redmi Note 7 (without the "Pro"), because it's a modern phone that is working reasonable well with Ubuntu Touch. The online shop where I bought it from let me choose some options, including the RAM size, so I chose the maximum available (6GB) without being aware that this would mean that I would be buying the "Pro" device - the shop did not alter the item name, so I couldn't really know. Unfortunately, the two versions are two rather different beasts, powered by different SoC; both are produced by Qualcomm, so they are not that different, but it's enough to make the installation of Ubuntu Touch impossible.

But between the choice of retuning the phone to the shop and begin a new porting adventure, I stood firm and went for the latter. Hopefully I won't regret it (if everything goes bad, I can still use it with LineageOS, which runs perfectly on it).

Moreover, there already exist a port of Ubuntu Touch for this phone, which actually works reasonably well (I tried it briefly, and many things were working), but the author claims to be a novice and indeed did not follow the best git practices when working on the source code, so it's hard to understand what was changed and why. But if you are looking for a quick way to get Ubuntu Touch working on this phone, you are welcome to have a look at this Telegram channel.

What follows are the raw notes of my attempts. They are here so that search engines can index the error messages and the various logs, and hopefully help someone hitting similar errors on other devices to find his way out.

Getting Halium and the device source code

Installed the dependencies like in the first step. repo was not found in the Ubuntu 20.04 archives, but I had it installed anyway due to my work on a Yocto device.

Since my device has Android 9 on it, I went for Halium 9:

repo init -u git://github.com/Halium/android.git -b halium-9.0 --depth=1
repo sync -c -j 16

The official LineageOS repository for the Xiaomi Redmi Note 7 Pro is android_device_xiaomi_violet, but the page with the official build has been taken down (some DMCA violation, if you believe the forums) and no development has been happening since last year. A more active forum thread uses another repository which seems to be receiving more frequent updates, so I chose to base my port on that.

I actually tested that LineageOS image on my phone, and verified that all the hardware was working properly.

Initially, I created forks of the relevant repository under my own gitlab account, but then I though (especially looking at the Note 7 port) that creating a group just for this port would make people's life easier, because they wouldn't need to navigate through my 1000 personal projects to find what is relevant for this port. So, I created these forks:

Next, created the halium/devices/manifests/xiaomi_violet.xml file with this content:

<?xml version="1.0" encoding="UTF-8"?>
    <!-- Remotes -->
    <remote name="ubuntu-touch-xiaomi-violet"

    <!-- Device Tree -->
    <project path="device/xiaomi/violet"
             remote="ubuntu-touch-xiaomi-violet" />

    <!-- Kernel -->
    <project path="kernel/xiaomi/violet"
             remote="ubuntu-touch-xiaomi-violet" />

    <!-- Proprietary/Vendor blobs -->
    <project path="vendor/xiaomi/violet"
             remote="ubuntu-touch-xiaomi-violet" />

Fetching all the sources mentioned in the manifest:

./halium/devices/setup violet

Full output:

I: Configuring for device xiaomi_violet
Fetching projects: 100% (393/393), done.
hardware/qcom/audio-caf/apq8084: Shared project LineageOS/android_hardware_qcom_audio found, disabling pruning.
hardware/qcom/audio-caf/msm8916: Shared project LineageOS/android_hardware_qcom_audio found, disabling pruning.
hardware/qcom/audio-caf/msm8952: Shared project LineageOS/android_hardware_qcom_audio found, disabling pruning.
hardware/qcom/audio-caf/msm8960: Shared project LineageOS/android_hardware_qcom_audio found, disabling pruning.
hardware/qcom/audio-caf/msm8974: Shared project LineageOS/android_hardware_qcom_audio found, disabling pruning.
hardware/qcom/audio-caf/msm8994: Shared project LineageOS/android_hardware_qcom_audio found, disabling pruning.
hardware/qcom/audio-caf/msm8996: Shared project LineageOS/android_hardware_qcom_audio found, disabling pruning.
hardware/qcom/audio-caf/msm8998: Shared project LineageOS/android_hardware_qcom_audio found, disabling pruning.
hardware/qcom/audio-caf/sdm845: Shared project LineageOS/android_hardware_qcom_audio found, disabling pruning.
hardware/qcom/audio-caf/sm8150: Shared project LineageOS/android_hardware_qcom_audio found, disabling pruning.
hardware/qcom/audio/default: Shared project LineageOS/android_hardware_qcom_audio found, disabling pruning.
hardware/qcom/display: Shared project LineageOS/android_hardware_qcom_display found, disabling pruning.
hardware/qcom/display-caf/apq8084: Shared project LineageOS/android_hardware_qcom_display found, disabling pruning.
hardware/qcom/display-caf/msm8916: Shared project LineageOS/android_hardware_qcom_display found, disabling pruning.
hardware/qcom/display-caf/msm8952: Shared project LineageOS/android_hardware_qcom_display found, disabling pruning.
hardware/qcom/display-caf/msm8960: Shared project LineageOS/android_hardware_qcom_display found, disabling pruning.
hardware/qcom/display-caf/msm8974: Shared project LineageOS/android_hardware_qcom_display found, disabling pruning.
hardware/qcom/display-caf/msm8994: Shared project LineageOS/android_hardware_qcom_display found, disabling pruning.
hardware/qcom/display-caf/msm8996: Shared project LineageOS/android_hardware_qcom_display found, disabling pruning.
hardware/qcom/display-caf/msm8998: Shared project LineageOS/android_hardware_qcom_display found, disabling pruning.
hardware/qcom/display-caf/sdm845: Shared project LineageOS/android_hardware_qcom_display found, disabling pruning.
hardware/qcom/display-caf/sm8150: Shared project LineageOS/android_hardware_qcom_display found, disabling pruning.
hardware/qcom/media: Shared project LineageOS/android_hardware_qcom_media found, disabling pruning.
hardware/qcom/media-caf/apq8084: Shared project LineageOS/android_hardware_qcom_media found, disabling pruning.
hardware/qcom/media-caf/msm8916: Shared project LineageOS/android_hardware_qcom_media found, disabling pruning.
hardware/qcom/media-caf/msm8952: Shared project LineageOS/android_hardware_qcom_media found, disabling pruning.
hardware/qcom/media-caf/msm8960: Shared project LineageOS/android_hardware_qcom_media found, disabling pruning.
hardware/qcom/media-caf/msm8974: Shared project LineageOS/android_hardware_qcom_media found, disabling pruning.
hardware/qcom/media-caf/msm8994: Shared project LineageOS/android_hardware_qcom_media found, disabling pruning.
hardware/qcom/media-caf/msm8996: Shared project LineageOS/android_hardware_qcom_media found, disabling pruning.
hardware/qcom/media-caf/msm8998: Shared project LineageOS/android_hardware_qcom_media found, disabling pruning.
hardware/qcom/media-caf/sdm845: Shared project LineageOS/android_hardware_qcom_media found, disabling pruning.
hardware/qcom/media-caf/sm8150: Shared project LineageOS/android_hardware_qcom_media found, disabling pruning.
hardware/ril: Shared project LineageOS/android_hardware_ril found, disabling pruning.
hardware/ril-caf: Shared project LineageOS/android_hardware_ril found, disabling pruning.
hardware/qcom/wlan: Shared project LineageOS/android_hardware_qcom_wlan found, disabling pruning.
hardware/qcom/wlan-caf: Shared project LineageOS/android_hardware_qcom_wlan found, disabling pruning.
hardware/qcom/bt: Shared project LineageOS/android_hardware_qcom_bt found, disabling pruning.
hardware/qcom/bt-caf: Shared project LineageOS/android_hardware_qcom_bt found, disabling pruning.
Updating files: 100% (67031/67031), done.nel/testsUpdating files:  36% (24663/67031)
lineage/scripts/: discarding 1 commits
Updating files: 100% (1406/1406), done.ineageOS/android_vendor_qcom_opensource_thermal-engineUpdating files:  47% (666/1406)
Checking out projects: 100% (392/392), done.
I: Refreshing device vendor repository: device/xiaomi/violet
I: Processing proprietary blob file: device/xiaomi/violet/./proprietary-files.txt
I: Processing fstab file: device/xiaomi/violet/./rootdir/etc/fstab.qcom
I: Removing components relying on SettingsLib from: device/xiaomi/violet

Starting the build

Setting up the environment:

$ source build/envsetup.sh
including device/xiaomi/violet/vendorsetup.sh
including vendor/lineage/vendorsetup.sh

Running the breakfast command:

$ breakfast violet
including vendor/lineage/vendorsetup.sh
Trying dependencies-only mode on a non-existing device tree?

PRODUCT_SOONG_NAMESPACES= hardware/qcom/audio-caf/sm8150 hardware/qcom/display-caf/sm8150 hardware/qcom/media-caf/sm8150

Building the kernel

The configuration needs to be adapted for Halium. Locating the kernel config:

$ grep "TARGET_KERNEL_CONFIG" device/xiaomi/violet/BoardConfig.mk 
TARGET_KERNEL_CONFIG := vendor/violet-perf_defconfig

Getting the Mer checker tool and running it:

git clone https://github.com/mer-hybris/mer-kernel-check
cd mer-kernel-check
./mer_verify_kernel_config ../kernel/xiaomi/violet/arch/arm64/configs/vendor/violet-perf_defconfig

Prints lots of warnings, starting with:

WARNING: kernel version missing, some reports maybe misleading

To help the tool, we need to let him know the kernel version. It can be seen at the beginning of the kernel Makefile, located in ../kernel/xiaomi/violet/Makefile; in my case it was


So I edited the configuration file ../kernel/xiaomi/violet/arch/arm64/configs/vendor/violet-perf_defconfig and added this line at the beginning:

# Version 4.14.83

then ran the checker tool again. This time the output was a long list of kernel options that needed to be fixed, but as I went asking for some explanation in the Telegram channel for Ubuntu Touch porters, I was told that I could/should skip this test and instead use the check-kernel-config tool from Halium. I downloaded it, made it executable (chmod +x check-kernel-config) and ran it:

./check-kernel-config kernel/xiaomi/violet/arch/arm64/configs/vendor/violet-perf_defconfig
[...lots of red and green lines...]
Config file checked, found 288 errors that I did not fix.

I ran it again with the -w option, and it reportedly fixed 287 errors. Weird, does that mean that an error was still left? I ran the tool again (without -w), and it reported 2 errors. Ran it once more in write mode, and if fixed them. So, one might need to run it twice.

Next, added the line

BOARD_KERNEL_CMDLINE += console=tty0

in device/xiaomi/violet/BoardConfig.mk. One more thing that needs to be done before starting the build is fixing the mount points, so I opened device/xiaomi/violet/rootdir/etc/fstab.qcom and changed the type of the userdata partition from f2fs to ext4. There were no lines with the context option, so that was the only change I needed to do.

At this point, while browsing throught the documentation, I found a link to this page which contains some notes on Halium 9 porting, which are substantially different from the official porting guide in halium.org (which I was already told in Telegram to be obsolete in several points).

So, following the instructions from this new link I ran

hybris-patches/apply-patches.sh --mb

which completed successfully.

Then, continuing following the points from this page, I edited device/xiaomi/violet/lineage_violet.mk, commented out the lines

$(call inherit-product, $(SRC_TARGET_DIR)/product/full_base_telephony.mk)
# ...
$(call inherit-product, vendor/lineage/config/common_full_phone.mk)

and replaced the first one with a similar line pointing to halium.mk. For the record, a find revealed that the SRC_TARGET_DIR variable in my case was build/make/target/. It contained also the halium.mk file, which was created by the hybris patches before. As for removing the Java dependencies, I cound't find any modules similar to those listed in this commit in any of the makefiles in my source tree, so I just started the build:

source build/envsetup.sh && breakfast violet
make halium-boot

This failed the first time with the compiler being killed (out of memory, most likely), but it succeeded on the second run. There was a suspicious warning, though:

drivers/input/touchscreen/Kconfig:1290:warning: multi-line strings not supported

And indeed my kernel/xiaomi/violet/drivers/input/touchscreen/Kconfig had this line:

source "drivers/input/touchscreen/ft8719_touch_f7b/Kconfig

(notice the unterminated string quote). I don't know if this had any impact on the build, but just to be on the safe side I added the missing quote and rebuilt.

Building the system image


make systemimage

failed pretty soon:

ninja: error: '/home/mardy/projects/port/halium/out/soong/host/linux-x86/framework/turbine.jar', needed by '/home/mardy/projects/port/halium/out/soong/.intermediates/libcore/core-oj/android_common/turbine/core-oj.jar', missing and no known rule to make it

The error is due to all the Java-related stuff that I should have disabled but couldn't find. So, I tried to have a look at the changes made on another xiaomi device (lavender, the Redmi note 7, which might not be that different, I thought) and started editing device/xiaomi/violet/device.mk and removing a couple of Android packages. Eventually the build proceeded, just to stop at a python error:

  File "build/make/tools/check_radio_versions.py", line 56
    print "*** Error opening \"%s.sha1\"; can't verify %s" % (fn, key)
SyntaxError: invalid syntax

Yes, it's the python3 vs python2 issue, since in my system python is python version 3. In order to fix it, I created a virtual environment:

virtualenv --python 2.7 ../python27  # adjust the path to your prefs
source ../python27/bin/activate

Remember that the second line must be run every time you'll need to setup the Halium build environment (that is, every time you run breakfast).

The build then proceeded for several minutes, until it failed due to some unresolved symbols:

prebuilts/gcc/linux-x86/aarch64/aarch64-linux-android-4.9/aarch64-linux-android/bin/ld.gold: error: /home/mardy/projects/port/halium/out/target/product/violet/obj/STATIC_LIBRARIES/lib_driver_cmd_qcwcn_intermediates/lib_driver_cmd_qcwcn.a: member at 7694 is not an ELF object
external/wpa_supplicant_8/hostapd/src/drivers/driver_nl80211.c:7936: error: undefined reference to 'wpa_driver_set_p2p_ps'
/home/mardy/projects/port/halium/out/target/product/violet/obj/EXECUTABLES/hostapd_intermediates/src/drivers/driver_nl80211.o:driver_nl80211.c:wpa_driver_nl80211_ops: error: undefined reference to 'wpa_driver_set_ap_wps_p2p_ie'
/home/mardy/projects/port/halium/out/target/product/violet/obj/EXECUTABLES/hostapd_intermediates/src/drivers/driver_nl80211.o:driver_nl80211.c:wpa_driver_nl80211_ops: error: undefined reference to 'wpa_driver_get_p2p_noa'
/home/mardy/projects/port/halium/out/target/product/violet/obj/EXECUTABLES/hostapd_intermediates/src/drivers/driver_nl80211.o:driver_nl80211.c:wpa_driver_nl80211_ops: error: undefined reference to 'wpa_driver_set_p2p_noa'
/home/mardy/projects/port/halium/out/target/product/violet/obj/EXECUTABLES/hostapd_intermediates/src/drivers/driver_nl80211.o:driver_nl80211.c:wpa_driver_nl80211_ops: error: undefined reference to 'wpa_driver_nl80211_driver_cmd'

As people told me in the Telegram channel, this driver is not used since "our wpa_supplicant talks to kernel directly". OK, so I simply disabled the driver, copying again from the lavender Halium changes: commented out the BOARD_WLAN_DEVICE := qcwcn line (and all lines referring this variable) from device/xiaomi/violet/BoardConfig.mk and ran make systemimage again. This time, surprisingly, it all worked.

Try it out

I first tried to flash the kernel only. I rebooted into fastboot, and on my PC ran this:

fastboot flash boot halium-boot.img

I then rebooted my phone, but after showing the boot logo for a few seconds it would jump to the fastboot screen. Indeed, flashing the previous kernel would restore the normal boot, so there had to be something wrong with my own kernel.

While looking at what the problem could be, I noticed that in the lavender port the author did not modify the lineageos kernel config file in place, but instead created a new one and changed the BoardConfig.mk file to point to his new copy. Since it sounded like a good idea, I did the same and created kernel/xiaomi/violet/arch/arm64/configs/vendor/violet_halium_defconfig for the Halium changes. And then the line in the board config file became

TARGET_KERNEL_CONFIG := vendor/violet_halium_defconfig

I then continued investigating the boot issue, and I was told that it might have been due to an Android option, skip_initramfs, which is set by the bootloader and causes our Halium boot to fail. The fix is to just disable this option in the kernel, by editing init/initramfs.c and change the skip_initramfs_param function to always set the do_skip_initramfs variable to 0, rather than to 1. After doing this, the boot proceeded to show the Ubuntu splash screen with the five dots being lit, but it didn't proceed from there.

Setting up the udev rules

Even in this state, the device was detected by my host PC and these lines appeared in the system log:

kernel: usb 1-3: new high-speed USB device number 26 using xhci_hcd
kernel: usb 1-3: New USB device found, idVendor=0fce, idProduct=7169, bcdDevice= 4.14
kernel: usb 1-3: New USB device strings: Mfr=1, Product=2, SerialNumber=3
kernel: usb 1-3: Product: Unknown
kernel: usb 1-3: Manufacturer: GNU/Linux Device
kernel: usb 1-3: SerialNumber: GNU/Linux Device on usb0

Indeed, I guess the reason I could do this without even flashing my systemimage is because I had first flashed another UT system image from another porter. I'm not sure if I'd had the same results with my own image. Anyway, the USB networking was there, so I connected and ran the following commands to generate the udev rules:

ssh phablet@
# used 0000 as password
sudo -i
# same password again
cd /home/phablet
cat /var/lib/lxc/android/rootfs/ueventd*.rc /vendor/ueventd*.rc \
        | grep ^/dev \
        | sed -e 's/^\/dev\///' \
        | awk '{printf "ACTION==\"add\", KERNEL==\"%s\", OWNER=\"%s\", GROUP=\"%s\", MODE=\"%s\"\n",$1,$3,$4,$2}' \
        | sed -e 's/\r//' \

I then copied (with scp) this file to my host PC, and I moved it to device/xiaomi/violet/ubuntu/70-violet.rules (I had to create the ubuntu directory first). Then I edited the device/xiaomi/violet/device.mk file and added these lines at the end:

### Ubuntu Touch ###
### End Ubuntu Touch ###

It was now time to try my own system image. I rebooted my device into TWRP, I cloned the halium-install repository into my halium build dir, downloaded a rootfs for Halium9, and ran

./halium-install/halium-install -p ut \
    ~/Downloads/ubuntu-touch-android9-arm64.tar.gz \

The first time this failed because the simg2img tool was not installed. The second time it proceeded to create the image, asked me for a password for the phablet user (gave "0000") and pushed the image onto the device, into the /data/ partition. I then rebooted.

My first Ubuntu Touch image

Upon reboot, the usual splash screen appeared, followed by several seconds of black screen. It definitely didn't look right, but at least it proved that something had been flashed. After some more seconds, to my big surprise, the Ubuntu boot screen appeared, just with a smaller logo than how it used to be before, which also confimed that my system image was being used - in fact, I did not adjust the GRID_UNIT_PX variable before. Since this was an easy fix, I chose to focus on that, rather than fix the boot issues (indeed, my device did not move on from the Ubuntu boot screen). SSH was working.

I took the scaling.conf file from the lavender changes, put it in device/xiaomi/violet/ubuntu/ and added this line in the PRODUCT_COPY_FILES in device.mk:


I initially used system/ubuntu/etc/... as the target destination for the config file, like in the lavender commit, but this didn't work out for me. Then I changed the path to start with system/halium/, like it's mentioned in the ubports documentation, but it apparently had no effect either.

After a couple of days spent trying to understand why my files were not appearing under /etc, it turned out that the device was not using my system image at all: with halium-install I had my image installed in /userdata/system.img, while the correct path for Halium 9 devices is /userdata/android-rootfs.img. I was told that the option -s of halium-install would do the trick. Instead of re-running the script, I took the shortcut of renaming /userdata/system.img to /userdata/android-rootfs.img and after rebooting I could see that the Ubuntu logo was displayed at the correct size. And indeed my system image was being used.

So I started to debug why unity8 didn't start. The logs terminated with this line:

terminate called after throwing an instance of 'std::runtime_error'
  what():  org.freedesktop.DBus.Error.NoReply: Message recipient disconnected from message bus without replying
initctl: Event failed

It means, that unity8 did not handle correctly the situation where another D-Bus service crashed while handing a call from unity8. The problem now was how to figure out which service it was. I ran dbus-monitor and restarted unity8 (initctl start unity8), then examined the dbus logs; I saw the point where unity8 got disconnected from the bus, but before that point I didn't find any failed D-Bus calls. So it had to be the system bus. I did exactly the same steps, just this time after running dbus-monitor --system as root, I found the place where unity8 got disconnected, and found this D-bus error shortly before that:

method call time=1605676421.968667 sender=:1.306 -> destination=com.ubuntu.biometryd.Service serial=3 path=/default_device; interface=com.ubuntu.biometryd.Device; member=Identifier
method return time=1605676421.970222 sender=:1.283 -> destination=:1.306 serial=4 reply_serial=3
   object path "/default_device/identifier"
method call time=1605676421.974218 sender=:1.283 -> destination=org.freedesktop.DBus serial=6 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=GetConnectionAppArmorSecurityContext
   string ":1.306"
error time=1605676421.974278 sender=org.freedesktop.DBus -> destination=:1.283 error_name=org.freedesktop.DBus.Error.AppArmorSecurityContextUnknown reply_serial=6
   string "Could not determine security context for ':1.306'"
signal time=1605676421.989074 sender=org.freedesktop.DBus -> destination=:1.283 serial=6 path=/org/freedesktop/DBus; interface=org.freedesktop.DBus; member=NameLost
   string "com.ubuntu.biometryd.Service"
error time=1605676421.989302 sender=org.freedesktop.DBus -> destination=:1.306 error_name=org.freedesktop.DBus.Error.NoReply reply_serial=4
   string "Message recipient disconnected from message bus without replying"

So, it looks like unity8 (:1.306) made a request to biometryd, who asked the D-Bus daemon what was the AppArmor label of the caller, but since I didn't backport the D-Bus mediation patches for AppArmor, the label could not be resolved. biometryd decided to crash instead of properly handling the error, and so did unity8.

So I backported the AppArmor patches. I took them from the Canonical kernel repo, but they did not apply cleanly because they are meant to be applied on top of a pristine 4.14 branch, whereas the Android kernel had already some AppArmor security fixes backported from later releases. So I set and quickly inspected the contents of each patch, and found out that a couple of them had already been applied, and the last patch had to be applied as the first (yeah, it's hard to explain, but it all depends on other patches that Android has backported from newer kernels). Anyway, after rebuilding the kernel and reflashing it, my phone could finally boot to unity8!

Conclusion (of the first episode)

The actual porting, as I've been told, starts here. What has been documented here are only the very first steps of the bring-up; what awaits me now is to make all the hardware subsystems work properly, and this, according to people more experienced in porting, is the harder part.

So far, very few things work, to the point that it's faster to me to list the things that do work; it's safe to assume that all what is not listed here is not working:

  • Mir, with graphics and input: Unity8 starts and is usable
  • Camera: can take photos; video recording start but an error appears when the stop button is pressed
  • Flashlight
  • Fingerprint reader: surprisingly, this worked out of the box
  • Screen brightness (though it can be changed only manually)

For all the rest, please keep an eye on this blog: I'll write, when I make some progress!

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17 Jan 2021 7:15pm GMT

15 Jan 2021

feedAndroid Developers Blog

MAD Skills Kotlin and Jetpack: wrap-up

Posted by Florina Muntenescu, Developer Relations Engineer

Kotlin and Jetpack image

We just wrapped up another series of MAD Skills videos and articles - this time on Kotlin and Jetpack. We covered different ways in which we made Android code more expressive and concise, safer, and easy to run asynchronous code with Kotlin.

Check out the episodes below to level up your Kotlin and Jetpack knowledge! Each episode covers a specific set of APIs, talking both about how to use the APIs but also showing how APIs work under the hood. All the episodes have accompanying blog posts and most of them link to either a sample or a codelab to make it easier to follow and dig deeper into the content. We also had a live Q&A featuring Jetpack and Kotlin engineers.

Episode 1 - Using KTX libraries

In this episode we looked at how you can make your Android and Jetpack coding easy, pleasant and Kotlin-idiomatic with Jetpack KTX extensions. Currently, more than 20 libraries have a KTX version. This episode covers some of the most important ones: core-ktx that provides idiomatic Kotlin functionality for APIs coming from the Android platform, plus a few Jetpack KTX libraries that allow us to have a better user experience when working with APIs like LiveData and ViewModel.

Check out the video or the article:

Episode 2 - Simplifying APIs with coroutines and Flow

Episode 2, covers how to simplify APIs using coroutines and Flow as well as how to build your own adapter using suspendCancellableCoroutine and callbackFlow APIs. To get hands-on with this topic, check out the Building a Kotlin extensions library codelab.

Watch the video or read the article:

Episode 3 - Using and testing Room Kotlin APIs

This episode opens the door to Room, peeking in to see how to create Room tables and databases in Kotlin and how to implement one-shot suspend operations like insert, and observable queries using Flow. When using coroutines and Flow, Room moves all the database operations onto the background thread for you. Check out the video or blog post to find out how to implement and test Room queries. For more hands-on work - check out the Room with a view codelab.

Episode 4 - Using WorkManager Kotlin APIs

Episode 4 makes your job easier with WorkManager, for scheduling asynchronous tasks for immediate or deferred execution that are expected to run even if the app is closed or the device restarts. In this episode we go over the basics of WorkManager and look a bit more in depth at the Kotlin APIs, like CoroutineWorker.

Find the video here and the article here, but nothing compares to practical experience so go through the WorkManager codelab.

Episode 5 - Community tip

Episode 5 is by Magda Miu - a Google Developer Expert on Android who shared her experience of leveraging foundational Kotlin APIs with CameraX. Check it out here:

Episode 6 - Live Q&A

In the final episode we launched into a live Q&A, hosted by Chet Haase, with guests Yigit Boyar - Architecture Components tech lead, David Winer - Kotlin product manager, and developer relations engineers Manuel Vivo and myself. We answered questions from you on YouTube, Twitter and elsewhere.

15 Jan 2021 2:08pm GMT

17 Dec 2020

feedPlanet Maemo

Avast, Qt6 announcing new QPromise and QFuture APIs

Qt published its New_Features in Qt 6.0.

Some noteworthy items in their list:

I like to think I had my pirate-hook in it at least a little bit with QTBUG-61928.

I need to print this out and put it above my bed:
Thiago Macieira added a comment - 13 Jul '17 03:51
You're right
Philip Van Hoof added a comment - 13 Jul '17 07:32
Damn, and I was worried the entire morning that I had been ranting again.
Thiago Macieira added a comment - 13 Jul '17 16:06
oh, you were ranting. Doesn't mean you're wrong.
Thanks for prioritizing this Thiago.

0 Add to favourites0 Bury

17 Dec 2020 9:29pm GMT

16 Dec 2020

feedAndroid Developers Blog

Treble Plus One Equals Four

Posted by Iliyan Malchev (Project Treble Architect), Amith Dsouza (Technical Account Manager) , and Veerendra Bhora (Strategic Partnerships Manager)

Illustration of phone with settings logo in the screen

Extending Android updates on Qualcomm's Mobile Platforms

In the past few years, the latest Android OS has been adopted earlier by OEMs and deployed in larger numbers to our users. The growth in adoption has been driven by OEMs delivering faster OS updates, taking advantage of the architecture introduced by Project Treble.

At the time Android 11 launched there were 667M active users on Android 10, 82% of whom got their Android 10 build via an over the air (OTA) update. Despite the events throughout 2020, there is a continued momentum among our partners to either launch their devices on Android 11 or offer Android 11 OTAs on their devices earlier.

Line graph comparing Android Pie, Android 10, and Android 11

Our efforts till now have been focussed on making OS updates easier and faster to deploy. The other side of this coin is supporting updates for a longer period of time, and today we'd like to provide an overview of the changes we are making to help our partners achieve this.

Project Treble was an ambitious re-architecture of Android that created a split between the OS framework and device-specific low-level software (called the vendor implementation) through a well-defined, stable vendor interface. As a part of this split, the Android OS framework guarantees backward compatibility with the vendor implementation, which is checked through a standardized compliance test suite - VTS. With each Android release, Project Treble publishes Generic System Images (GSIs) that are built from AOSP sources, and are guaranteed to be backwards-compatible with the previous 3 versions of vendor implementations, in addition of course to the current release-for a total span of four years. Devices launching with the new Android release must have vendor implementations compatible with that GSI. This is the primary vehicle for reducing fragmentation within the OS framework. While we allow and encourage our partners to modify the framework itself, the modifications post-Treble must be done in a way that reduces upgrade costs from one version to the next.

Besides the reuse of a vendor implementation across OS updates, the Treble architecture also facilitates the re-use of the same OS framework code across different vendor implementations.

Chart comparing Original OS framework to Updated OS framework

Another important change introduced by Project Treble is that new vendor-impacting requirements for Android devices are never retroactive. They apply only to devices launching on that Android version and not to devices upgrading from an older version. The term vendor-impacting here refers to requirements for new HALs, or for the shipping of a newer Linux kernel, to the device's vendor implementation. A good example might be a new revision of the camera HAL to support multiple rear camera sensors. Since the Android framework guarantees compatibility with the older HALs, we enable older vendor implementations to be reused by OEMs for upgrades without the considerable cost of updating them with new requirements.

This principle, combined with the backwards-compatibility guarantee, gives device manufacturers (OEMs) the flexibility to support upgrades both faster (since they have to upgrade just the framework, which would cover all of their devices, including those with older versions of the vendor implementation), as well as at a lower cost (since they do not have to touch the older vendor implementations).

However, seen from a System-on-Chip manufacturers' perspective, this design introduces additional complexity. For each SoC model, the SoC manufacturers now needed to create multiple combinations of vendor implementations to support OEMs who would use that chipset to launch new devices and deploy OS upgrades on previously launched devices.

The result is that three years beyond the launch of a chipset, the SoC vendor would have to support up to 6 combinations of OS framework software and vendor implementations. The engineering costs associated with this support limited the duration for which SoC vendors offered Android OS software support on a chipset. For every single chipset, the software support timeline would look like this:

Timeline of OS framework

Considering that SoC providers have dozens of SoC models at any point of time, the full picture looks closer to this:

More accurate support timeline

The crux of the problem was that, while device requirements were never retroactive, the requirements for SoCs were. For example on Android Pie, SoCs had to support two versions of the Camera HAL API on a chipset if it was used to support new device launches and upgrades.

From this perspective, the solution was simple: we had to extend the no-retroactivity principle to the SoCs as well as to devices. With this change, the SoC provider would be able to support Android with the same vendor implementations on their SoCs for device launches as well as upgrades.

During the past year, we have been working hard to implement this solution. Building on our deep collaboration with our colleagues at Qualcomm, today we're announcing the results of this work. Going forward, all new Qualcomm mobile platforms that take advantage of the no-retroactivity principle for SoCs will support 4 Android OS versions and 4 years of security updates. All Qualcomm customers will be able to take advantage of this stability to further lower both the costs of upgrades as well as launches and can now support their devices for longer periods of time.

Going one step further, we're also reusing the same OS framework software across multiple Qualcomm chipsets. This dramatically lowers the number of OS framework and vendor implementation combinations that Qualcomm has to support across their mobile platforms and results in lowered engineering, development, and deployment costs. The diagram below indicates how significant the simplification is. From a software-support perspective, it's an altogether different situation:

Framework timeline with simplification

This change is taking effect with all SoCs launching with Android 11 and later. By working closely with Qualcomm to offer an extended period of OS and security updates, we are looking forward to delivering the best of Android to our users faster, and with greater security for an extended period of time.

16 Dec 2020 6:03pm GMT

Opening the Google Play Store for more car apps

Posted by Eric Bahna, Product Manager

In October, we published the Android for Cars App Library to beta so you could start bringing your navigation, parking, and charging apps to Android Auto. Thanks for sending your feedback with our issue tracker, so we know where to improve and clarify things. Now we're ready to take the next step in delivering great in-car experiences.

Today, you can publish your apps to closed testing tracks in the Google Play Store. This is a great way to get feedback on how well your app meets the app quality guidelines, plus get your in-car experience in front of your first Android Auto users.

 Image of T map
Image of PlugShare
 Image of 2GIS

Three of our early access partners: T map, PlugShare,and 2GIS

We're preparing the Play Store for open testing tracks soon. You can get your app ready today by publishing to closed testing. We're eager to see what you've built!

16 Dec 2020 4:53pm GMT

06 Dec 2020

feedPlanet Maemo

How to generate random points on a sphere

This question often pops up, when you need a random direction vector to place things in 3D or you want to do a particle simulation.

We recall that a 3D unit-sphere (and hence a direction) is parametrized only by two variables; elevation \theta \in [0; \pi] and azimuth \varphi \in [0; 2\,\pi] which can be converted to Cartesian coordinates as

\begin{aligned} x &= \sin\theta \, \cos\varphi \\ y &= \sin\theta \, \sin\varphi \\ z &= \cos\theta \end{aligned}

If one takes the easy way and uniformly samples this parametrization in numpy like

phi = np.random.rand() * 2 * np.pi
theta = np.random.rand() * np.pi

One (i.e. you as you are reading this) ends with something like this:

While the 2D surface of polar coordinates uniformly sampled (left), we observe a bias of sampling density towards the poles when projecting to the Cartesian coordinates (right).
The issue is that the cos mapping of the elevation has an uneven step size in Cartesian space, as you can easily verify: cos^{'}(x) = sin(x).

The solution is to simply sample the elevation in the Cartesian space instead of the spherical space - i.e. sampling z \in [-1; 1]. From that we can get back to our elevation as \theta = \arccos z:

z = 1 - np.random.rand() * 2 # convert rand() range 0..1 to -1..1
theta = np.arccos(z)

As desired, this compensates the spherical coordinates such that we end up with uniform sampling in the Cartesian space:

Custom opening angle

If you want to further restrict the opening angle instead of sampling the full sphere you can also easily extend the above. Here, you must re-map the cos values from [1; -1] to [0; 2] as

cart_range = -np.cos(angle) + 1 # maximal range in cartesian coords
z = 1 - np.random.rand() * cart_range
theta = np.arccos(z)

Optimized computation

If you do not actually need the parameters \theta, \varphi, you can spare some trigonometric functions by using \sin \theta = \sqrt { 1 - z^2} as

\begin{aligned} x &= \sqrt { 1 - z^2} \, \cos\varphi \\ y &= \sqrt { 1 - z^2} \, \sin\varphi \end{aligned} 0 Add to favourites0 Bury

06 Dec 2020 1:12am GMT

25 Sep 2017

feedPlanet Openmoko

Holger "zecke" Freyther: Brain dump what fascinates me

A small brain dump of topics that currently fascinate me. These are mostly pointers and maybe it is interesting to follow it.


My kobo ebook reader has the Site Reliability Engineering book and I am now mostly done. It is kind of a revelation and explains my interest to write code but also to operate infrastructure (like struggling with ruby, rmagick, nginx…). I am interested in backends since… well ever. The first time I noticed it when we talked about Kolab at LinuxTag and I was more interested in the backend than the KDE client. At sysmocom we built an IoT product and the backend was quite some fun, especially the scale of one instance and many devices/users, capacity planning and disk commissioning, lossless upgrades.

It can be seen in my non FOSS SS7 map work on traffic masquerading and transparent rewriting. It is also clear to see which part of engineering is needed for scale (instead of just installing and restarting servers).

Lang VM design

One technology that made Java fast (Hotspot) and has seen its way into JavaScript is dynamic optimization. Most Just in Time Compilers start with generating native code per method, either directly or after the first couple of calls when the methods size is significant enough. The VM records which call paths are hot, which types are used and then can generate optimized code (e.g. specialized for integers, remove type checks). A technique pioneered at Sun for the "Self" language (and then implemented for Strongtalk and then brought to Java) was "adaptive optimization and deoptimization" and was the Phd topic of Urs Hoelzle (Google's VP of Engineering). One of the key aspects is inlining across method boundaries as this removes method look-up, call stack handling and opens the way for code optimization across method boundaries (at the cost of RAM usage).

In OpenJDK, V8 and JavaScriptCore this adaptive optimization is typically implemented in C++ and requires quite some code. The code is complicated as it needs to optimize but also need to return to a basic function (deoptimize, e.g. if a method changed or the types passed don't match anymore), e.g. in the middle of a for loop with tons of inlined code (think of Array.map being inlined but then need to be de-inlined). A nice and long blog post of JSC can be found here describing the On Stack Replacement (OSR).

Long introduction and now to the new thing. In the OpensmalltalkVM a new approach called Sista has been picked and I find it is genius. Like with many problems the point of view and approach really matters. Instead of writing a lot of code in the VM the optimizer runs next to the application code. The key parts seem to be:

The revelation is the last part. By just optimizing from bytecode to bytecode the VM remains in charge of creating and managing machine code. The next part is that tooling in the higher language is better or at least the roundtrip is more quick (edit code and just compile the new method instead of running make, c++, ld). The productivity thanks to the abstraction and tooling is likely higher.

As last part the OSR is easier as well. In Smalltalk thisContext (the current stack frame, activation record) is an object as well. At the right point (when the JIT has either written back variables from register to the stack or at least knows where the value is) one can just manipulate thisContext, create and link news ones and then resume execution without all the magic in other VMs.

Go, Go and escape analysis

Ken Thompson and Robert Pike are well known persons and their Go programming language is a very interesting system programming language. Like with all new languages I try to get real world experience with the language, the tooling and which kind of problems can be solved with it. I have debugged and patched some bigger projects and written two small applications with it.

There is plenty I like. The escape analysis of the compiler is fun (especially now that I know it was translated from the Plan9 C compiler from C to Go), the concurrency model is good (though allowing shared state), the module system makes sense (but makes forking harder than necessary), being able to cross compile to any target from any system.

Knowing a bit of Erlang (and continuing to read the Phd Thesis of Joe Armstrong) and being a heavy Smalltalk user there are plenty of things missing. It starts with vague runtime error messages (e.g. panicslice not having parameters) and goes to runtime and post-runtime inspection. In Smalltalk thanks to the abstraction a lot of hard things are easy and I would have wished for some of them to be in Go. Serialize all unrecovered panics? Debugging someone else's code seems like pre 1980…

So for many developers Go is a big improvement but for some people with a wider view it might look like a lost opportunity. But that can only be felt by developers that have experienced higher abstraction and productivity.

Unsupervised machine learning

but that is for another dump…

25 Sep 2017 10:11am GMT

02 Sep 2017

feedPlanet Openmoko

Harald "LaF0rge" Welte: Purism Librem 5 campaign

There's a new project currently undergoing crowd funding that might be of interest to the former Openmoko community: The Purism Librem 5 campaign.

Similar to Openmoko a decade ago, they are aiming to build a FOSS based smartphone built on GNU/Linux without any proprietary drivers/blobs on the application processor, from bootloader to userspace.

Furthermore (just like Openmoko) the baseband processor is fully isolated, with no shared memory and with the Linux-running application processor being in full control.

They go beyond what we wanted to do at Openmoko in offering hardware kill switches for camera/phone/baseband/bluetooth. During Openmoko days we assumed it is sufficient to simply control all those bits from the trusted Linux domain, but of course once that might be compromised, a physical kill switch provides a completely different level of security.

I wish them all the best, and hope they can leave a better track record than Openmoko. Sure, we sold some thousands of phones, but the company quickly died, and the state of software was far from end-user-ready. I think the primary obstacles/complexities are verification of the hardware design as well as the software stack all the way up to the UI.

The budget of ~ 1.5 million seems extremely tight from my point of view, but then I have no information about how much Puri.sm is able to invest from other sources outside of the campaign.

If you're a FOSS developer with a strong interest in a Free/Open privacy-first smartphone, please note that they have several job openings, from Kernel Developer to OS Developer to UI Developer. I'd love to see some talents at work in that area.

It's a bit of a pity that almost all of the actual technical details are unspecified at this point (except RAM/flash/main-cpu). No details on the cellular modem/chipset used, no details on the camera, neither on the bluetooth chipset, wifi chipset, etc. This might be an indication of the early stage of their plannings. I would have expected that one has ironed out those questions before looking for funding - but then, it's their campaign and they can run it as they see it fit!

I for my part have just put in a pledge for one phone. Let's see what will come of it. In case you feel motivated by this post to join in: Please keep in mind that any crowdfunding campaign bears significant financial risks. So please make sure you made up your mind and don't blame my blog post for luring you into spending money :)

02 Sep 2017 10:00pm GMT

01 Sep 2017

feedPlanet Openmoko

Harald "LaF0rge" Welte: First actual XMOS / XCORE project

For many years I've been fascinated by the XMOS XCore architecture. It offers a surprisingly refreshing alternative virtually any other classic microcontroller architectures out there. However, despite reading a lot about it years ago, being fascinated by it, and even giving a short informal presentation about it once, I've so far never used it. Too much "real" work imposes a high barrier to spending time learning about new architectures, languages, toolchains and the like.

Introduction into XCore

Rather than having lots of fixed-purpose built-in "hard core" peripherals for interfaces such as SPI, I2C, I2S, etc. the XCore controllers have a combination of

  • I/O ports for 1/4/8/16/32 bit wide signals, with SERDES, FIFO, hardware strobe generation, etc
  • Clock blocks for using/dividing internal or external clocks
  • hardware multi-threading that presents 8 logical threads on each core
  • xCONNECT links that can be used to connect multiple processors over 2 or 5 wires per direction
  • channels as a means of communication (similar to sockets) between threads, whether on the same xCORE or a remote core via xCONNECT
  • an extended C (xC) programming language to make use of parallelism, channels and the I/O ports

In spirit, it is like a 21st century implementation of some of the concepts established first with Transputers.

My main interest in xMOS has been the flexibility that you get in implementing not-so-standard electronics interfaces. For regular I2C, UART, SPI, etc. there is of course no such need. But every so often one encounters some interface that's very rately found (like the output of an E1/T1 Line Interface Unit).

Also, quite often I run into use cases where it's simply impossible to find a microcontroller with a sufficient number of the related peripherals built-in. Try finding a microcontroller with 8 UARTs, for example. Or one with four different PCM/I2S interfaces, which all can run in different clock domains.

The existing options of solving such problems basically boil down to either implementing it in hard-wired logic (unrealistic, complex, expensive) or going to programmable logic with CPLD or FPGAs. While the latter is certainly also quite interesting, the learning curve is steep, the tools anything but easy to use and the synthesising time (and thus development cycles) long. Furthermore, your board design will be more complex as you have that FPGA/CPLD and a microcontroller, need to interface the two, etc (yes, in high-end use cases there's the Zynq, but I'm thinking of several orders of magnitude less complex designs).

Of course one can also take a "pure software" approach and go for high-speed bit-banging. There are some ARM SoCs that can toggle their pins. People have reported rates like 14 MHz being possible on a Raspberry Pi. However, when running a general-purpose OS in parallel, this kind of speed is hard to do reliably over long term, and the related software implementations are going to be anything but nice to write.

So the XCore is looking like a nice alternative for a lot of those use cases. Where you want a microcontroller with more programmability in terms of its I/O capabilities, but not go as far as to go full-on with FPGA/CPLD development in Verilog or VHDL.

My current use case

My current use case is to implement a board that can accept four independent PCM inputs (all in slave mode, i.e. clock provided by external master) and present them via USB to a host PC. The final goal is to have a board that can be combined with the sysmoQMOD and which can interface the PCM audio of four cellular modems concurrently.

While XMOS is quite strong in the Audio field and you can find existing examples and app notes for I2S and S/PDIF, I couldn't find any existing code for a PCM slave of the given requirements (short frame sync, 8kHz sample rate, 16bit samples, 2.048 MHz bit clock, MSB first).

I wanted to get a feeling how well one can implement the related PCM slave. In order to test the slave, I decided to develop the matching PCM master and run the two against each other. Despite having never written any code for XMOS before, nor having used any of the toolchain, I was able to implement the PCM master and PCM slave within something like ~6 hours, including simulation and verification. Sure, one can certainly do that in much less time, but only once you're familiar with the tools, programming environment, language, etc. I think it's not bad.

The biggest problem was that the clock phase for a clocked output port cannot be configured, i.e. the XCore insists on always clocking out a new bit at the falling edge, while my use case of course required the opposite: Clocking oout new signals at the rising edge. I had to use a second clock block to generate the inverted clock in order to achieve that goal.

Beyond that 4xPCM use case, I also have other ideas like finally putting the osmo-e1-xcvr to use by combining it with an XMOS device to build a portable E1-to-USB adapter. I have no clue if and when I'll find time for that, but if somebody wants to join in: Let me know!

The good parts

Documentation excellent

I found the various pieces of documentation extremely useful and very well written.

Fast progress

I was able to make fast progress in solving the first task using the XMOS / Xcore approach.

Soft Cores developed in public, with commit log

You can find plenty of soft cores that XMOS has been developing on github at https://github.com/xcore, including the full commit history.

This type of development is a big improvement over what most vendors of smaller microcontrollers like Atmel are doing (infrequent tar-ball code-drops without commit history). And in the case of the classic uC vendors, we're talking about drivers only. In the XMOS case it's about the entire logic of the peripheral!

You can for example see that for their I2C core, the very active commit history goes back to January 2011.

xSIM simulation extremely helpful

The xTIMEcomposer IDE (based on Eclipse) contains extensive tracing support and an extensible near cycle accurate simulator (xSIM). I've implemented a PCM mater and PCM slave in xC and was able to simulate the program while looking at the waveforms of the logic signals between those two.

The bad parts

Unfortunately, my extremely enthusiastic reception of XMOS has suffered quite a bit over time. Let me explain why:

Hard to get XCore chips

While the product portfolio on on the xMOS website looks extremely comprehensive, the vast majority of the parts is not available from stock at distributors. You won't even get samples, and lead times are 12 weeks (!). If you check at digikey, they have listed a total of 302 different XMOS controllers, but only 35 of them are in stock. USB capable are 15. With other distributors like Farnell it's even worse.

I've seen this with other semiconductor vendors before, but never to such a large extent. Sure, some packages/configurations are not standard products, but having only 11% of the portfolio actually available is pretty bad.

In such situations, where it's difficult to convince distributors to stock parts, it would be a good idea for XMOS to stock parts themselves and provide samples / low quantities directly. Not everyone is able to order large trays and/or capable to wait 12 weeks, especially during the R&D phase of a board.

Extremely limited number of single-bit ports

In the smaller / lower pin-count parts, like the XU[F]-208 series in QFN/LQFP-64, the number of usable, exposed single-bit ports is ridiculously low. Out of the total 33 I/O lines available, only 7 can be used as single-bit I/O ports. All other lines can only be used for 4-, 8-, or 16-bit ports. If you're dealing primarily with serial interfaces like I2C, SPI, I2S, UART/USART and the like, those parallel ports are of no use, and you have to go for a mechanically much larger part (like XU[F]-216 in TQFP-128) in order to have a decent number of single-bit ports exposed. Those parts also come with twice the number of cores, memory, etc- which you don't need for slow-speed serial interfaces...

Insufficient number of exposed xLINKs

The smaller parts like XU[F]-208 only have one xLINK exposed. Of what use is that? If you don't have at least two links available, you cannot daisy-chain them to each other, let alone build more complex structures like cubes (at least 3 xLINKs).

So once again you have to go to much larger packages, where you will not use 80% of the pins or resources, just to get the required number of xLINKs for interconnection.

Change to a non-FOSS License

XMOS deserved a lot of praise for releasing all their soft IP cores as Free / Open Source Software on github at https://github.com/xcore. The License has basically been a 3-clause BSD license. This was a good move, as it meant that anyone could create derivative versions, whether proprietary or FOSS, and there would be virtually no license incompatibilities with whatever code people wanted to write.

However, to my very big disappointment, more recently XMOS seems to have changed their policy on this. New soft cores (released at https://github.com/xmos as opposed to the old https://github.com/xcore) are made available under a non-free license. This license is nothing like BSD 3-clause license or any other Free Software or Open Source license. It restricts the license to use the code together with an XMOS product, requires the user to contribute fixes back to XMOS and contains references to importand export control. This license is incopatible with probably any FOSS license in existance, making it impossible to write FOSS code on XMOS while using any of the new soft cores released by XMOS.

But even beyond that license change, not even all code is provided in source code format anymore. The new USB library (lib_usb) is provided as binary-only library, for example.

If you know anyone at XMOS management or XMOS legal with whom I could raise this topic of license change when transitioning from older sc_* software to later lib_* code, I would appreciate this a lot.

Proprietary Compiler

While a lot of the toolchain and IDE is based on open source (Eclipse, LLVM, ...), the actual xC compiler is proprietary.

Further Reading

01 Sep 2017 10:00pm GMT

12 Nov 2011

feedPlanet Linux-to-go

Paul 'pfalcon' Sokolovsky: Shopping for 3D TV...

Shopping for 3D TV (again), few findings:

12 Nov 2011 6:55pm GMT

Paul 'pfalcon' Sokolovsky: Hacking Luxeon SP-1

I finally going to get Arduino, and while I'm choosing flavor and waiting for it, I can't help but disassembling all devices I have at home, each time speaking: "This must have Arduino inside!" (meaning of course that I expect it to be based on general-purpose MCU). Gosh, I usually get "blob chip" (uncased chip with blob of epoxy on top).

Well, I finally had my expectations fulfilled - Luxeon SP-1 voltage stabilizer/cutter features ATMEGA48V-10PU (Flash: 4k, EEPROM: 256, RAM:512). Not only that, it is installed in DIP socket! Buy from Luxeon, they're hacker-friendly ;-).

I bought the device actually for a wattmeter it features (which fact is hard to figure out from common specs found in the shops, I accidentally read somebody mentioning it on a forum). The wattmeter is of course not bright - for a lamp rated 100W it shows 88W, and for more powerful equipment (like perforator) understates wattage even more (maybe it's difference between real and apparent power factor).

Still, for $17 you get Arudino-alike with voltage/current sensor and hacking possibility. Woot!

High-power board:

MCU board:

12 Nov 2011 5:58pm GMT

10 Nov 2011

feedPlanet Linux-to-go

Paul 'pfalcon' Sokolovsky: Links for November 2011


Linux kernel module tricks:

10 Nov 2011 3:21pm GMT

19 Oct 2011

feedPlanet OpenEZX

Antonio Ospite: Gnome 3: go to Shell? Not just yet, thanks.

In Debian Unstable the transition to Gnome 3 is taking place; when Gnome 3.0 firstly came out some unnamed geeky users complained loudly about the design decisions of the development team to push strongly towards gnome-shell as a new default UI; gnome-shell was designed focusing on usability (usability is a metric relative to a certain target audience BTW) and simplicity, hiding a lot of details from the users. Obviously you can never make everyone happy so some of us simply happened to be "out of target": you know us computer people (*cough cough*), we like to be in charge and control The Machine... I must admit I still don't have a definitive opinion about the gnome-shell concept, for now I just know that it does not suit me; I am going to try it eventually, maybe I'll get used to it, but in the mean time I need my desktop back just like I shaped it through the years; can this be done without loosing all the good Gnome technologies (Empathy over all of them)?

To be completely fair I have to say that there is little to complain about with Gnome developers, we can still get our good old GNOME desktop fully back by using the fall-back mode based on gnome-panel and live happily ever after, let's take a look at how this can be accomplished.

NOTE: GNOME people state that the fall-back mode is meant for systems with older graphic cards which cannot run gnome-shell, however it can very well be seen as a good opportunity for those who do not want to run gnome-shell just yet.

Getting back to the topic: some minor touches are needed to make the panel look more like what we are used to, maybe some of these settings could even become default for fall-back mode, we'll see.

First, enable fall-back mode (on Debian there is a dedicated session you can choose from the Log-in Manager for that) and change some desktop settings, in a terminal type:

$ gsettings set org.gnome.desktop.session session-name 'gnome-fallback'
$ gsettings set org.gnome.desktop.interface 'menus-have-icons' true
$ gsettings set org.gnome.desktop.interface 'buttons-have-icons' true
$ gsettings set org.gnome.desktop.background 'show-desktop-icons' true

gnome-tweak-tool can be used for some of these settings like shown in the attached images.

Then rearrange the applets on the panel as you please (use Alt-RightClick to access the panel properties), and fix the theming using this patch to have a light panel again (against gnome-themes-standard=3.0.2-1):

$ mkdir $HOME/.themes
$ cd $HOME/.themes
$ cp -r /usr/share/themes/Adwaita Adwaita-fallback
$ cd Adwaita-fallback
$ patch -p1 < $HOME/adwaita-fallback-panel-theme.patch
$ gsettings set org.gnome.desktop.interface 'gtk-theme' 'Adwaita-fallback'

Some final touches for the Metacity window manager and to the clock applet, and we are all set:

$ gconftool-2 --type string --set /apps/metacity/general/focus_mode mouse
$ gconftool-2 --type boolean --set /apps/metacity/general/compositing_manager true
$ gconftool-2 --type string --set /apps/panel3-applets/clock/custom_format '<span color="#333">%a %d %b</span> <b>%H:%M</b>'
$ gconftool-2 --type string --set /apps/panel3-applets/clock/format custom

Ah, in the new gnome-panel based on Gtk3 there are still some details to take care of, I hope issues like that will be addressed and that the panel will be supported for quite some time.

Attached images:
Gnome Shell default look on Debian
gnome-tweak-tool show desktop icons
Gnome 3 fall-back mode default look on Debian
Gnome 3 fall-back mode applets rearranged
Gnome 3 fall-back mode rethemed to have a light panel
Attached files:
text/x-diff iconAdwaita theme patch for fall-back mode

19 Oct 2011 9:37pm GMT

09 Jun 2011

feedPlanet OpenEZX

Michael Lauer: The Eagle Has Landed!

After letting us wait for a bit longer than scheduled (13 days), the hospital initiated the contractions. For the first couple of hours, everything went just perfect, but then the little one got stuck on the way and we had to resort to a cesarean section. Lara Marie Lauer was born 8th of June at 04:41 (AM) with 3460 gramms and 49 cm.

Mummy was still on intensive care and so they gave her to me. I can't express the feelings I had in this very moment. I'm still kind of overwhelmed every time I see her. Thanks for all of you who waited anxiously with me and those who prayed for us. The most important tasks for the near future is getting Mummy to recover and Lara Marie to become accustomed to us and the rest of the outside world.

Please bear with me if in the next time I'm not as responsive as usually :)

Lara Marie Lauer

09 Jun 2011 4:06pm GMT

30 May 2011

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Michael Lauer: German Post on time!

And now for something completely different… while we are all waiting for my baby to arrive (who was scheduled for 25th of May), she just received her first greeting card - together with a personalized bib and a towel (with integrated hood - pretty fancy!) from my good friends at #openmoko-cdevel.

Guys, seeing this card was very heartwarming - it means a lot to me that you share my anticipation, thanks a lot! And I'm 100% sure she will appreciate her gifts… now let's cross fingers it won't take much longer… waiting is the hardest part of it :)



30 May 2011 8:54am GMT