Re: [Xenomai] Xenomai on Udoo Neo

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

On Tue, May 24, 2016 at 03:28:08PM +0200, mfinkbei wrote:
> Am 2016-05-23 09:59, schrieb Gilles Chanteperdrix:
> > On Mon, May 23, 2016 at 09:49:18AM +0200, mfinkbei wrote:
> >> Hi,
> > 
> > Hi,
> > 
> >> 
> >> I am writing to request some Details about the Xenomai using for an 
> >> Udoo
> >> Neo.
> >> In my currently Thesis I'm working for the first time with an 
> >> real-time
> >> System.
> >> One objective therefore is to install Xenomai 3 on the Udoo Neo board
> >> with an iMX6 multicore Processor.
> >> For the board exist a Linux-Version on the base of the Linux kernel
> >> 3.14.56.
> >> For this kernel Version there no i-pipe patch available. This is why I
> >> was looking for differences in the affected Files of the kernel 
> >> 3.14.44
> >> and 3.14.56 and Change the i-pipe-patch when there are differences.
> >> Afterwards, I was able to patch the Udoo Neo Kernel, to make the 
> >> config,
> >> the bzImage and the modules and Install it from an Computer with
> >> Linux-OS to the SD-Card as described in the Documentation.
> >> At that time of the Installation I kept on working with the Udoo Neo
> >> Board. For Configuring and building the ARM libraries I use the 
> >> commands
> >> ./scripts/bootstrap
> >> sudo ../configure CFLAGS="-march=armv7-a" LDFLAGS="-march=armv7-a"
> >> --with-core=cobalt --enable-smp
> >> 
> >> After the make install Command I wanted to test the Installation with
> >> dmesg | grep -i xenomai
> >> where I get the Output
> >> 
> >> [    0.147853] [^[[01;31m^[[KXenomai^[[m^[[K] scheduling class idle
> >> registered.
> >> [    0.147865] [^[[01;31m^[[KXenomai^[[m^[[K] scheduling class rt
> >> registered.
> >> [    0.148004] [^[[01;31m^[[KXenomai^[[m^[[K] init failed, code -19
> >> 
> >>   the full dmesg output in this time frame is
> >> 
> >> [    0.146610] Bus freq driver module loaded
> >> [    0.147489] futex hash table entries: 256 (order: 2, 16384 bytes)
> >> [    0.147909] [Xenomai] scheduling class idle registered.
> >> [    0.147921] [Xenomai] scheduling class rt registered.
> >> [    0.148021] I-pipe: high-resolution clock not working
> > 
> > Xenomai on cortex a9 uses the global timer as its high resolution
> > clock source. AFAICT, you have not enabled the global timer in the
> > kernel configuration, so you simply need to enable it.
> > 
> > Also note that board-specific kernels drivers have generally a lower
> > quality than the mainline kernel, because they are not reviewed by
> > the Linux kernel community. So, rather than working with
> > board-specific kernel, it is advised to cleanup the board specific
> > drivers you need and submit them to the mainline kernel, so as to
> > get reviewed, which improves the drivers quality. And when it is
> > done, you no longer need the board-specific kernel.
> > 
> > Regards.
> 
> Thank you for your answer.
> The CONFIG_ARM_GLOBAL_TIMER is already enabled.

Not in the kernel configuration you have sent to this list and that
is available here:
https://xenomai.org/pipermail/xenomai/attachments/20160523/1ce893f7/attachment.ksh

> I also noticed that a mainline kernel would be better, especially for 
> newbies in Xenomai.
> But the main scope of my master thesis includes the work with that 
> developing board and the multicore Processor. The realisation of an 
> real-time-system for the A9 Processor is just necessary for my work. I'm 
> not familiar with the driver development, so it's not possible for me, 
> to fix the problems there in reasonable time.
> I've recognized, that the drivers have a lower quality and didn't 
> support the frequency scaling switch. For this reason I'm searching for 
> a possibility to install Xenomai with enabled frequency scaling and then 
> disabling the frequency scaling outside the kernel.

Enabling frequency scaling should not prevent Xenomai from starting.
The issue you have is unrelated to frequency scaling.

-- 
					    Gilles.
https://click-hack.org