Tag Archives: linux

RF433 – Raspberry PI GPIO kernel driver for interrupt management

You may have read some of my post about RF433 and Raspberry PI. Basically with RPI 1, I was using wiringPi interrupt handler to manage the RF433 decoding. The problem is that with RPI2 and RPI B+ the delay to take an interrupt that was becomes unpredictable. And the timing constraints are not respected. As a consequence part of the messages are loss because for these delay.

One of the solution (the software one) is to be more efficient to proceed the interrupts and the way to do this is to compile a kernel driver for directly handling the interrupts. This is what this post is about. This comes to complete the RFRPI code and associated hardware. A complete source code and software for using it is on the rfrpi bitbucket repository.

Challenge of the coming days : write a kernel driver to manage interruption quicker on a raspberry pi 2. I’m happy to find a lot of example on Internet and in particular this one, that is really looking like what I’m trying to do. This post is describing all the step needed to do this.

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Configure internal Lan & OpenVPN on Azure

If you want to create a company like infrastruture on Azure you could expect to create a VPN to have a secured access to it and have an internal lan to protect you servers against external access. Basically the system provides all that you need but, as usual in the closed world of MicroSoft. The VPN server based on SSTP protocol sound hard and not documented to be used with MacOsX or Linux.

I’ll describe in this post how I fixed this issue par using an OpenVpn gateway server.

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Why Docker sounds like a revolution ?

20140418-082531.jpgThese two last days, I was participating to devoxx in Paris. One of the star topic of the event this year was Docker so I attempt different talk about this container technology I already has discovered in a previous JUG session. It was not an evidence that this technology was more than something interesting for DEV needing small, fast starting, small memory footprint, environment for testing. With my OPS hat, I did not catch the interest. This was before Devoxx and the different talk. The aspects I’ll detailed in this post have not been addressed during Devoxx, as much as I have seen, as mostly the DEV aspects have been addressed, I going to synthesize my opinion.

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Small ODROID-U3 platform coming out !

Really interesting tweet I just saw about the Odroid-U3 platform you can find following this link. This platform with the size of a Raspberry PI board is a 4 ARM core 1.7Gb (cortex A9) with 2GB included. Video is HDMI 1080p.Storage is MicroSD slot. The price is really low : 58$

You can ran even Android & Linux on it.

Compared to a RPI, this sound good for video/media box applications, better than RPI. For hacking this is largely different, as you can see on the picture, GPIO connector are not so easy to access. But, you can also purchase an extension shield providing all what you are expected with 36 GPIO. To build your own shield it could be more complicated than RPI. This let me go to a question I have since months … Why RPI is not becoming less and less expensive or more & more powerful ? it have now about 2 year old.

Less negative point : like any new board coming after Raspberry, the ecosystem is actually really smaller and all third party components (box, shields) is really limited.

Now, that said … I have to order one !

ODROID-U3
ODROID-U3
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Problem with nvidia raid and grub2

It’s not the first time I have some trouble to setup grub2 correctly with my nvidia raid system (also called fake-raid) … I did not find exactly why, but for sure i never try to install grub2 correctly from yast or in manual mode.

The first solution to find was : how to boot a fresh installed system when the bootloader has not been configured. The solution is here : http://www.supergrubdisk.org. This tool is really simple and so efficient to boot !  I recommend to have this in your linux emergency kit !

The second solution, once the system has start is to reinstall a bootloader. Here, in fact the solution is easy : destroy this f**** grub2 and replace it by the legacy really good grub ! lol

Then it works … last step to me: understand why gnome is taking so long to start ?!? or the answer is in the question …

I love Linux !

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