Fully Preemptible kernels

[Igor]

Available for:

 

4.13.10 cubox (Cubox-i, Hummingboards)
4.13.10 mvebu64 (Espressobin)
4.9.58  odroidxu4 (Odroid XU3/XU4)
4.13.10 rockchip (Tinkerboard, MiQi)
4.13.10 sunxi (All Allwinner 32bit boards)
4.13.10 sunxi64 (All Allwinner 64bit boards)

 

https://dl.armbian.com/_misc/realtime-kernel

Requirements:

- Armbian OS. Ubuntu or Debian bases.
- root credentials

Download: *dtb and *image packages at a minimum and install them with dpkg -i *.deb ... If you want to stay on this kernel, freeze upgrades in armbian-config -> system -> freeze kernel upgrades.

Remember that those kernels are bleeding edge, made from upstream sources and may have troubles. Consider them as is/experimental, without end-user support. If you want to build them - patches are present but .disabled and might not apply cleanly with more recent sources without adjustements.
 

What is RT?

[gahabana]

 

hi @Igor

thank you for the tip !

Did go and download XU4 RT kernel .debs installed and at reboot did not get usual blue-light kernel heart-beat.

 

Thought maybe something was wrong with my image (built using instructions) and i downloaded the one https://dl.armbian.com/odroidxu4/Ubuntu_xenial_next.7z burned, booted, all usual - added user, rebooted one more time and then installed realtime kernel.

When i power it on afterwards - same issue - blue light changes every 10-15seconds from off to on (no heaertbeat). can not ping it.

Is there a tested scenario where you did get RT kernel to work on that i could try to replicate please ?

 

thanks so much !

 

[Igor]

No, those are first testing build of RT kernel for XU4, not very well tested. I will try to look into this when possible.

[gahabana]

1 hour ago, Igor said:

No, those are first testing build of RT kernel for XU4, not very well tested. I will try to look into this when possible.

Thanks Igor !

For what it is worth - i tried building it 2-3 weeks ago with then current RT-patch that is included in Armbian and yesterday with latest from rt-patches repository (for 4.9.61 kernel at https://www.kernel.org/pub/linux/kernel/projects/rt/4.9/patches-4.9.61-rt61.tar.gz ).

Either one (self built/latest) behave the same ... if it helps

thank you !

[sevi_at]

hy Igor,

thanks for your information. Yesterday I switched to a RT kernel according to your instructions. My Thinkerboard work as a LogitechMediaServer with more then one squeezelite instance, librespot, MPD, shairplay, etc.

it works!

 

however, one thing does not work anymore the playback of my line input. it overrides and emits a very damaged sound.

this command worked fine with kernel 4.4.73-rockchip:

arecord -f S16_LE -c2 -r44100 -d 0 -D plug:dsnoop01 | aplay -B 1 -D plug:LineIn01 

I also tried csound but here I have the same problem.

 

my Kernel version now:

4.13.10-rt3-rockchip

 

 

ask for info what could be the problem here and how I can solve it.

 

THX