iMX8 Yocto image with Fully Preemptible Kernel (RT) not available

Technical Support
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1

Dear Toradex Experts,

I followed other thread for bitbaking a Yocto image for my Apalis-iMX8 module with PREEMPT_RT patchset enabled. I started with Toradex BSP3.0 :

$ repo init -u http://git.toradex.com/toradex-bsp-platform.git -b LinuxImage3.0 -m default.xml

And from your documentation about Real-Time Linux, I modified the conf/local.conf as below :

MACHINE ?= "apalis-imx8x"

# Use this distro
DISTRO = "tdx-x11"
DISTRO_mx8 = "tdx-xwayland-rt"

ACCEPT_FSL_EULA = "1"

After bitbaking the qt5-x11-image, I checked by launching the kenel menuconfig, however I could select neither Preemptible Kernel (Basic RT) nor Fully Preemptible Kernel (RT) option since they are missing :

alt text

I would like to know if this is normal and what is the possible reason for NOT supporting these options, please ?

Thanks in advance and best regards,

/Khang

2

Hi

You found a bug in the apalis-imx8x machine configuration. This machine currently does not apply the RT patch when the RT distro is chosen.

You could try to add the following line to the machine configuration:
meta-toradex-nxp/conf/machine/apalis-imx8x.conf:

PREFERRED_PROVIDER_virtual/kernel_preempt-rt = "linux-toradex-rt"

A patch to fix that is on its way into thud-next.

Using linux-toradex-rt will also configure using PREMPT_RT_FULL by default.

Thank you for reporting this.
Max

3

Dear Max,

Thanks for your confirmation. I can see the patches are applied during bitbaking of kernel.