RT 4.19.71-rt24-v7l+ brakes USB on Raspberry PI 4 OS (Version 11/01/2021)

andypugh wrote:

alkabal wrote: After apt-get upgrade usb boot killed.

Try again on the sdcard instal kernel and edit /boot/config-rt.txt but this file seem to be missing :
vmlinuz-5.4.83-rt48-v7l+

The kernel deb installs a new kernel7l instead.

I have also try with this file (kernel7l) but i get "[brcmvirt_gpio_probe]: ]failed to dma_alloc_coherent(4096)"

Well, I am confused now.

Intending to investigate the effect of limiting memory to 3GB I made a new standard 32-bit SD card image, booted my new 2GB Pi4 (bought specifically to debug this reported issue) and followed the instructions here in the LinuxCNC docs:
linuxcnc.org/docs/2.8/html/getting-start...lling_on_raspbian_10
Contrary to the reports in this and other threads, it all "just worked".

I moved the SD card to my Pi400, and that worked, and then to my old 4GB Pi4, and that worked.

Is there _actually_ a problem?

And can we move all further discussion to this thread?
forum.linuxcnc.org/9-installing-linuxcnc...-work?start=0#194602