Build BalenaOS for jetson nx emmc - add custom KERNEL_ROOTSPEC


i am currently trying to get the edge TPU to work on the jetson nx emmc image. This could be solved for the jetson-nano by apending the KERNEL_ROOTSPEC with gasket.dma_bit_mask=32 pcie_aspm=off. Sadly changing the KERNEL_ROOTSPEC:jetson-xavier-nx-devkit-emmc (layers/meta-balena-jetson/recipes-kernel/linux/linux-tegra_%.bbappend) has no effect.
Since this flag is empty and the jetson nx does not use u-boot and is loading the kernel from a raw partition, the flags will probably need to be appended at another place. Could you point me in some direction?

Lastly i can not build a dev image by using the -d flag of barys. Did something change over the course of the past releases of barys or is this a issue with the xavier nx too?

Thank you for your support :slight_smile:

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Hey @Langhalsdino hope you are well!

Just one quick question: By “Edge TPU”, you are talking about this, correct? Products | Coral (scroll down about half-way, to “Production Products”). And if so, which one are you using, exactly?

In the meantime, @acostach – do you have any guidance on where Frederic can append kernel variables to get included in a local build of Jetson Xavier NX? What recipe handles kernel args on Xavier NX?

Yes, i am talking about the coral edge tpu pcie module. Specially about the dual edge tpu M.2 Accelerator with Dual Edge TPU | Coral . As described in the coral issue KERNEL_ROOTSPEC need to be added e.g. pcie_aspm=off".

Just in case some one else reads this:
In order to make the dual edge tpu work, you will need a pcie multiplexer . Otherwise just one will work :slight_smile:

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Hi @Langhalsdino , can you please try do the append to the OS_KERNEL_CMDLINE after:

eg: OS_KERNEL_CMDLINE:append = " pcie_aspm=off "


I will try it and flash the jetson tomorrow. Thank you :slight_smile:

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Thank you @acostach appending the OS_KERNEL_CMDLINE appears to be working. Furthermore appending KERNEL_ARGS is probably the cleaner way for the future.

I still struggle to get the gasket-dkms and apex recipe to work, but this is my code and my challenge :slight_smile: