For the Debian Technology Preview image for the Gemini PDA a monolithic kernel has been used. In order to get as many peripherals as possible working a modular kernel is necessary. So I decided to build a custom kernel.

Since the suspend on lid close feature only works with the community kernel, the kernel source from https://github.com/gemian/gemini-linux-kernel-3.18 has been used. After cloning I have followed the instructions on https://github.com/gemian/gemini-keyboard-apps/wiki/KernelCompilation. During kernel configuration I have changed the following options:

•Enabled kernel modules
•Enabled modules for nearly all USB devices
•Enabled modules for nearly all filesystems
•Enabled modules for nearly all encryptions/hashes/compressions
•Enabled multiple options for iptables
•Disabled ANDROID_PARANOID_NETWORK (for not having to add the user for every network service to the groups aid_inet_raw and aid_inet)
•Enabled CONFIG_JUMP_LABEL (for better performance)
•Enabled CONFIG_TASK_IO_ACCOUNTING (for using iotop)

This results in this kernel configuration: gemini-3.18.41+-config.gz (3038 downloads )

After building the kernel modules for the iptables MIRROR target (will not be usable with the default iptables version on the Gemini) and frandom have been added.

Those who do not want to go through this themselves can download my kernel from here:

Kernel Image: linux_boot-gemini-3.18.41+.img (510 downloads )
Modules: modules_firmware-gemini-3.18.41+.tar.gz (795 downloads )

Downloads outdated, new version at: Improved modular Linux kernel for the Gemini PDA

Instructions for flashing the image can be found on: support.planetcom.co.uk. Make sure to use the same scatter file that has been used for the initial flashing. Using the Download only mode of the flash tool is sufficient. Uncheck all partitions but linux_boot (or boot if you boot into linux as default). For the linux_boot respectively the boot partition select the downloaded kernel image. After flashing, copy the modules archive onto your Gemini and extract it in your root directory:

cd /
tar -xzf /path_to/modules_firmware-gemini-3.18.41+.tar.gz

After rebooting the device should feel a bit smoother and many USB peripherals should work.

Regards
Jürgen

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Last week my Gemini PDA has arrived. There have been some problems with devices from the first batch especially regarding the keyboard and the device not containing the X27 SoC but a X25 SoC.  At least one later device also has been reported being powered by the X25 SoC. Thus I wanted to do some basic testing before flashing Linux onto it. So I have installed CPUZ and A1 SD Bench on it and did some (very) basic testing.

First we will have a look at the CPUZ output. Here we can clearly see that this Gemini is powered by an X27 SoC with its two Cortex-A72 and eight Cortex A53.

Gemini PDA CPU – CPUZ screenshot

The last part of the SoC screen shows the Mali-T880 GPU.

Gemini GPU – CPUZ screenshot

Some more device information regarding display resolution and amount of memory can be seen below.

Gemini PDA device information – CPUZ screenshot

The two screenshots below show the sensors available in the Gemini. This might be interesting later to see if all of them can also be accessed from Linux.

Gemini PDA Sensors – CPUZ screenshot

Gemini PDA more Sensors – CPUZ screenshot

Finally some speed tests regarding the internal memory and the SD card using A1 SD Bench have been performed.

Gemini PDA memory bench – A1 SD Bench

The speed of the internal memory looks good, however it is strange that the write speed is shown to be faster than the read speed. This might be a bug in the benchmark app. Unfortunately the SD card speed of approximately 20MB/sec is disappointing. The SD card used is a U1/A1 capable SanDisk Ultra 200G which is rated up to 100 MB/sec for reading. Trying the same card with Linux and an USB3 card reader proves the spec:

# hdparm -t /dev/sdd1

/dev/sdd1:
Timing buffered disk reads: 280 MB in 3.00 seconds = 93.32 MB/sec

So there might be an incompatibility with this card or some driver issue. Maybe some later tests with Linux will show. At least the results would be comparable then, because of using the same tool.

The device seems to be as expected an after flashing Linux we can have a look into some more details.  The process of flashing Linux already is well documented on github and on oesf.org, thus it will not be covered here.

Stay tuned for updates.

Jürgen

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Posted in android, gadgets, linux | No Comments »

What is going on here? An unboxing article on MyGNU.de? Well, this is the exception, since the Gemini is an exceptional device like Nokias N900 has been before and in the future hopefully the some day finished  Neo900 might be. Well, I do not want to stray away any further. About 13 month ago I have backed Planet Computers Gemini PDA Indiegogo campaign. Planet Computers has promised a device that is different from anything else, that is available for purchase. The Gemini is a PDA class clamp-shell device with a fully integrated keyboard and touchscreen that is designed for Android, but also capable of running Linux. No need to go through the specs here, everything interesting regarding these can be read on Planet Computers web page or on Wikipedia. Last week, after a long time of waiting, the parcel with the 4G version of the Gemini, the connectivity kit and the optional camera finally arrived. The order id has been in the 20XX range and the device is with a non UK keyboard, so the device is most probably from the third batch.

Parcel containing the Gemini PDA

After opening the parcel and removing some wrapping material one can see multiple smaller boxes containing the device and its accessories.

The opened parcel

The boxes shown in the photo below contain from left to right, the leather pouch, the special HDMI adapter (only this one allows connecting an external display), the Gemini, the USB type C hub, the external camera addon and an additional charger.

Boxes containing the Gemini PDA and accessories

The larger box welcomes us with “hello” printed in several languages and contains  a smaller black box containing the manual and the cover removal tool (needed to insert a SIM card and a SD card), the PDA itself and (still in the larger box) a charger and the Type C to Type A USB cable.

The opened PDA box

Below we have a closer look to the PDA well wrapped in foil.

Gemini wrapped in foil

After removing the foil we can see its full beauty.

The Gemini PDA

With the opened device we can see the the display and the German QWERTZ keyboard. The keyboard feels solid and has no wobbly keys like it has been reported by backers who have received devices from the first batch.

The opened Gemini PDA with display and keyboard

Phone manufacturers recommend to charge the devices a first time fully before using. Most probably this is a myth without any use than having a fully charged device, but anyway I did.

Charging the Gemini PDA for the first time

I am hoping you have enjoyed the photo series. Further articles regarding testing some aspects of the device, Linux on the Gemini, and hopefully some solutions will follow. Does it really contain a X27 CPU? We will find out later. Stay tuned for updates.

Jürgen

(1 votes, average: 5.00 out of 5)

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After my last kernel upgrade I tried to build the iptables mirror target published the last time here. The iptables mirror target takes the packet sent to your machine and returns the same packet to the machine the packet came from. Thus, let’s say someone tries to scan your machine or tries an attack he would scan his own machine or even attack his own machine. When I tried it with kernel version 4.12 , it did not build anymore with the current linux kernel. This time a struct changed in kernel 4.10 and some functions have got renamed in the kernel 4.11. Thus I had to update the ip_direct_send and ipt_mirror_target functions. You can download the newer release for kernel version 4.10 and probably future kernels here:

MIRROR.4.10.tar.gz (9581 downloads )

The kernel module has been tested with kernel version 4.12.12-gentoo. To build the module, boot the kernel you want to use the module with. Afterwards unpack the archive and run the compile.sh script to build the module. Then run the install.sh script for installing the compiled module into the /lib/modules directory for your kernel.

Now you may use the mirror target in place of the REJECT or DROP target in the INPUT, FORWARD and PREROUTING chains, like this in your firewall script:

$IPTABLES -A INPUT -j MIRROR

Beware: The use of the mirror target may lead to strange results, in example if you want to connect to an iptables protected machine which uses the mirror target, you may end up connecting to the local machine without recognizing it. It also may use much bandwith. The worst case occurs if you have two machines using the module. These machines may end up playing ping pong. So you have been warned, use with caution and at your own risk. For more information see: MIRROR target.

Downloads for older kernel versions are below. Notice the version numbering 2.6.25 works for kernels up to 2.6.27. 2.6.28 also works for 2.6.29 and 2.6.30 kernels. The 2.6.13 version of the module should work up to kernel version 2.6.16.

regards
Jürgen

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Posted in kernel, linux, networking, security | 2 Comments »

Some months ago I got my brand new LG 55LA6608 3D TV. Of course I wanted to watch the 3d photos taken with the Fujifilm Finepix Real 3D camera with it. The images taken by the camera are being stored using the MPO file format. These images consist of two jpeg images and some metadata inside the exif header inside the MPO container. According to the specification the television is capable of playing this file format, which works fine when using in example an USB-stick. However, it is desireable to watch the images using a network connection, for example when the files are stored on a linux server.

For displaying videos or images from a server this and other television devices use the DLNA protocol, which is implemented by by various linux services like minidlna or ushare. None of the tested ones was capable to present the MPO files to the TV. The solution to enable ushare to do this is quite simple. The MPO mime type has to be added to ushares supported file formats. This can be done by adding the line

{ “mpo”,  UPNP_PHOTO, “http-get:*:image/mpo:”},

to the MIME_TYPE_LIST array in mime.c. This has been verified to work with the ushare-1.1a. For convenience one can download the patch for this from here:

ushare-mpo.patch (5773 downloads )

One can download the ushare sources from SourceForge. After downloading patch the ushare sources with the mpo-patch and build it. Build and usage instructions can be found in the readme file included in the ushare download from SourceForge. Do not forget to run ./configure –enable-dlna before running make for use with recent devices like the mentioned LG TV.

As usually, for gentoo users there is a more easy way: Create the directory

/etc/portage/patches/media-video/ushare/

and place the patch file in it. Make sure that the dlna USE-flag is set in /etc/make.conf or /etc/portage/package.use. Afterwards emerge ushare again and enjoy watching your 3D MPO images stored on your linux box using your TV.

regards

Jürgen

(1 votes, average: 5.00 out of 5)

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Posted in 3d, gentoo, linux, multimedia, networking | No Comments »

After my last kernel upgrade I tried to build the iptables mirror target published the last time here. The iptables mirror target takes the packet sent to your machine and returns the same packet to the machine the packet came from. Thus, let’s say someone tries to scan your machine or tries an attack he would scan his own machine or even attack his own machine. When I tried it with kernel version 3.6 , it did not build anymore with the current linux kernel. This time some functions have got removed from the kernel. Thus I had to update the ip_direct_send function. You can download the newer release for kernel version 3.6 and probably future kernels here:

MIRROR.3.6.0.tar.gz (10724 downloads )

The kernel module has been tested with kernel version 3.7.0-vs2.3.5.1. To build the module, boot the kernel you want to use the module with. Afterwards unpack the archive and run the compile.sh script to build the module. Then run the install.sh script for installing the compiled module into the /lib/modules directory for your kernel.

Now you may use the mirror target in place of the REJECT or DROP target in the INPUT, FORWARD and PREROUTING chains, like this in your firewall script:

$IPTABLES -A INPUT -j MIRROR

Beware: The use of the mirror target may lead to strange results, in example if you want to connect to an iptables protected machine which uses the mirror target, you may end up connecting to the local machine without recognizing it. It also may use much bandwith. The worst case occurs if you have two machines using the module. These machines may end up playing ping pong. So you have been warned, use with caution and at your own risk. For more information see: MIRROR target.

Downloads for older kernel versions are below. Notice the version numbering 2.6.25 works for kernels up to 2.6.27. 2.6.28 also works for 2.6.29 and 2.6.30 kernels. The 2.6.13 version of the module should work up to kernel version 2.6.16.

regards
Jürgen

(2 votes, average: 5.00 out of 5)

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Posted in kernel, linux, networking, security | No Comments »

After my last kernel upgrade I tried to build the iptables mirror target published here. The iptables mirror target takes the packet sent to your machine and returns the same packet to the machine the packet came from. Thus, let’s say someone tries to scan your machine or tries an attack he would scan his own machine or even attack his own machine. When I tried it with kernel version 3.3 , it did not build anymore with the current linux kernel. However, this time only a minor modification has been neccesary. Another header file had to be included and a function name has changed.  You can download the newer release for kernel version 3.3 and probably future kernels here:

[download#86]

The kernel module has been tested with kernel version linux-3.3-vserver-2.3.3.1. To build the module, boot the kernel you want to use the module with. Afterwards unpack the archive and run the compile.sh script to build the module. Then run the install.sh script for installing the compiled module into the /lib/modules directory for your kernel.

Now you may use the mirror target in place of the REJECT or DROP target in the INPUT, FORWARD and PREROUTING chains, like this in your firewall script:

$IPTABLES -A INPUT -j MIRROR

Beware: The use of the mirror target may lead to strange results, in example if you want to connect to an iptables protected machine which uses the mirror target, you may end up connecting to the local machine without recognizing it. It also may use much bandwith. The worst case occurs if you have two machines using the module. These machines may end up playing ping pong. So you have been warned, use with caution and at your own risk. For more information see: MIRROR target.

Downloads for older kernel versions are below. Notice the version numbering 2.6.25 works for kernels up to 2.6.27. 2.6.28 also works for 2.6.29 and 2.6.30 kernels. The 2.6.13 version of the module should work up to kernel version 2.6.16.

[download#45] [download#12] [download#13] [download#14] [download#32] [download#39] [download#46] [download#67] [download#73] [download#77]

regards
Jürgen

(2 votes, average: 5.00 out of 5)

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Posted in kernel, linux, networking, security | 1 Comment »