Building Qt for ARMv6l

mrjj

@Gutemberg
Ok. it sounds reasonable.
Good luck with it. sounds like interesting project.

Gutemberg

@mrjj Thanks... I hope someone can jump in here and bring me help building Qt for it... So far found no concrete document for that. But thanks

mrjj

@Gutemberg
well its seems to be mutiple disciplines into play as u want a custom Qt with very tight requirements but I bet
hard work and lots of asking here will enable u to build it.

Is it for a commercial product line or just a for fun project?

Gutemberg

@mrjj It is for a commercial project. At first we are aiming this PAX device since it is the more "flexible" device in the payment industry but we want to get other players supported as well (like Verifone, Ingenico, etc.).

Like I said, I tried to hire people just to build Qt for the device but no success. I found lots of people that know QML and development FOR Qt but none that actually cross compiled it for an embedded device.

tomasz3dk

Hi. Basically if you want to crosscompile qt you can do this in 2 ways:

If you have a proper toolchain and rootfs with development files, you can download qt sources and crosscompile it. I think that a good point to start is with begginsers guide for raspberry pi. Probably you will have to change some options in qmake.conf for this processor.
Build your own image and sdk with yocto project.

Qt Company have also Qt for device creation so you can ask them directly about commercial version for this device.
There are not much information about this device on internet (sdk, linux version etc..) so for now i can't help more.

Gutemberg

@tomasz3dk Thanks for get back. We cannot create an image for the device. We can only create applications for it. And yes, we have a toolchain with sysroot here. Tutorials like that one is one of the multiple ones around the web that points to specific PI build. There is no docs or tutorial for general ARM devices.

I updated the post with basic information of the device processor.

Thanks

tomasz3dk

@Gutemberg I don't see informations about processor in your first post ;)

Gutemberg

This post is deleted!

mrjj

@Gutemberg
Hi upload is broken here at forum ;(
please use external site and paste link here.

Gutemberg

@mrjj thanks!

@tomasz3dk here is the CPU info http://imageshack.com/a/img923/9276/3Zl3xf.png

Gutemberg

Ok good news!

I got Qt 5.8-beta compiled (didn't tried QtWebkit yet and previous versions don't compile, dunno why)! -> I'll post a complete step-by-step here once I got everything to work.

Sent to the device just the libQt5Core and a HelloWorld app that just write a line to the console I built with QtCreator and this is the output:

/data/opt/helloconsole $ ./HelloConsole
A newer kernel is required to run this binary. (__kernel_cmpxchg64 helper)

Any idea on what can be? As the image I posted here, the kernel is 3.0.56...

Thanks

jsulm

@Gutemberg said in Building Qt for ARMv6l:

__kernel_cmpxchg64

Does this happen with a plain C++ hello world application without Qt?
Here something about this issue: http://uhurumkate.blogspot.de/2014/07/a-newer-kernel-is-required-to-run-this.html
It should work with kernel >= 3.1

Gutemberg

@jsulm nop, other c++ apps ran just fine on the device. Only with Qt the problem happens...

Gutemberg

Hey guys, does anyone has any idea how to workaround this issue (except by upgrading kernel since it is not possible)?

We really want to buy Qt but we are struggling with this major blocker.

Thanks!

jsulm

@Gutemberg GCC < 4.7 could help. Did you check the link I provided? There are several suggestions which can help:

Enabling arm v7 hard-float might solve your problem (it solved mine).
Using -mfpu=vfp and -mfloat-abi=hard might solve your problem (i didn't try as armv7 was desired).

dsicari

Hello!! Do you have any news on it? Did you even run sme qt application on S920? If you did, can you tell us about?

thanks!