I have applied the PREEMPT_RT patch with no problems for the linux-toradex (kernel 4.4.21) supplied as part of the BSP 2.6.1beta, the same which contains the modules, device-trees and sources to the FreeRTOS support for the M4 core.
As for that, no problems at all. The system runs well. But I had problems with the autoload of the vf610_cm4_rproc module in this PREEMPT_RT Kernel for the VF61.
Enabling the module at startup, at most of the times the boot freezes or at the loading of systemv - random seed services/driver, or at the loading of the M4 Core itself. A few times the system is capable of booting with no problems.
Another problem is that, even loading the modules after the Linux boot, I cannot have a full operation of the imx_rproc_tty module, in other words, with a "modprobe imx_rproc_tty", I don't get a /dev/ttyRPMSG to use.
Could anyone give me a hand on this? I think the source of the problem could be how the v610_cm4_rproc or the random modules deal with the PREEMPT_RT "way".
Colibri Evaluation Board V3.2
Answer by andrecurvello · Feb 10 at 07:12 PM
Did you got any news about this topic/ticket?
Now I'm using the 4.4.39 kernel with rt50 patch. I
've disabled the remoteproc, usb and audio drivers/modules, and even yet I'm still having a "random" boot stuck issue.
In other words, I could say that almost in 5 out of 10 times the boot of my 4.4.39-rt Kernel got stuck.
Thanks for your attention.