Hello,
I am successfully using a bbai64 with a modified Dunfell-Yocto image based on TI-LINUX-SDK using BB.ORG linux-kernel-5.10.162-arm64 with a Intel ax200 wifi card. However, as soon as I switch to the linux-kernel-rt-5.10.162 (using same defconfig) the board boots fine, but it doesn’t find the Intel ax200 wifi card anymore - lspci doesn’t show a card pluged-in anymore.
Is this a known issue with the rt kernel?
Thanks a lot for your help,
have a nice day,
Bernd
Not sure if I would call it an “issue”. RT makes the kernel more deterministic and predictable. In doing so other stuff is prioritized differently and some is disabled.
Might look at your kernel config and see what is going on, might have to tweak a little bit. Keep in mind that when you change settings the deterministic nature of that kernel build will change.
Hello,
attached is the defconfig which I use for the linux-kernel-5.10.162-arm64 as well as linux-kernel-rt-5.10.162 - I intended to use it as a starting point before enabling RT in menuconfig. It is based on the bb.org defconfig for bbai64.
defconfig (207.8 KB)
Use $ diff <file a> <file b> it will show you the differences assuming both are in the same line by line order.
Hello,
@RobertCNelson: you write in the “AI-64 - RT Kernel?”(AI-64 - RT Kernel?) thread, that BeagleBone AI-64 “RT is still not booting on 5.10.x for us yet…” Do you know the reason why this fails?
Thanks a lot for your help Robert,
have a nice day,
Bernd
@foxsquirrel: did you read my previous posts? I run the BBAI64 with both the linux-kernel-rt-5.10.162 and the linux-kernel-5.10.162 while applying the same defconfig - which is the original BBAI64 defconfig from bb.org kernel repository (just turned off the compression for modules)! Thus there is no difference between the two defconfig’s.
Hi @bernd please give this a try with a spare image, (might not boot)…
sudo apt update
sudo apt install bbb.io-kernel-6.3-rt-k3
sudo reboot
It’s just mainline 6.3-rc3 + RT
Regards,
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Hello Robert,
unfortunately, the mainline 6.3-rc3-RT kernel has the same issue - lspci doesn’t list the intel ax200 wlan adapter…
I guess I have to wait until this issue is fixed and use as a work around a USB-based wifi adapter…
Thanks a lot for your help,
have a nice day,
Bernd
PS: The realtime-behaviour is much better with the BBAI64 than it is with the BBlue - I got now 2 CanOpen servo drives running in CSP @500Hz on the BBAI64 without any timing issues, whereas the BBlue didn’t manage to run those without timing issues @100Hz… (latest 5.10 rt kernel, disabled USB gadget)
@RobertCNelson
There are some changes related to PCIe-PLL setup in the kernel driver “drivers/phy/cadence/phy-cadence-sierra.c” in the bb.org-arm64 branch - Applying those changes to the ti-linux(-rt) branches fixes the pcie issue. Wifi with the Intel ax200 and a fully preempt-rt kernel works now like a charm… Making the bbai64 an ideal plattform for mobile-robotics
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Thanks for testing @bernd , pushed; add 0001-HACK-Sierra-Drive-clock-out.patch (3b4de6f4) · Commits · Robert Nelson / arm64-multiplatform · GitLab
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Hi guys,
Looks like lots of progress on this 
So what is now the easiest way to install the kernel, does sudo apt install bbb.io-kernel-6.3-rt-k3 now work?
Thanks
Andy
Correct, that’ll install it… Now that 6.4 is opening up, if there is a 6.4-rt branch, i’ll do the same…
Regards,
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