Michael,
I am not sure what you are trying to achieve, but I have some advice for you.
Here is what you need to do in local.conf:
MACHINE ?= "beaglebone"
PREFERRED_PROVIDER_virtual/kernel = "linux-yocto"
COMPATIBLE_MACHINE_beaglebone-yocto = "beaglebone-yocto"
Not sure what the last two commands should be, but you should NOT
mention any rt.
For -rt bbb you should set following options in virtual/kernel make menuconfig:
# CONFIG_SMP is not set
# CONFIG_MODULES is not set
CONFIG_DEBUG_ATOMIC_SLEEP=y
# CONFIG_DEBUG_LOCK_ALLOC is not set
# CONFIG_PROVE_LOCKING is not set
# CONFIG_LOCKDEP is not set
# CONFIG_CPU_FREQ is not set
# CONFIG_CPU_IDLE is not set
# CONFIG_NO_HZ is not set
CONFIG_HZ_PERIODIC=y
CONFIG_HZ_250=y
CONFIG_HZ=250
# CONFIG_SUSPEND is not set
# CONFIG_HIBERNATION is not set
# CONFIG_PM is not set
# CONFIG_FTRACE is not set
CONFIG_PREEMPT_RT_FULL=y
The commands to setup the menuconfig are the following:
[1] Run menuconfig and configure the kernel:
$ bitbake -c menuconfig virtual/kernel
[2] To save the configuration in a defconfig format:
$ bitbake -c savedefconfig virtual/kernel
https://variwiki.com/index.php?title=Yocto_Customizing_the_Linux_kernel
Then, you should have a bbb-rt kernel. With some tweaks and some
tricks... You'll find these for yourself!
Please, use the rt-tests package for testing kernel-bbb-rt.
My two cent worth answer,
Zee
_______
On Tue, Nov 1, 2022 at 1:54 PM Bruce Ashfield <[email protected]> wrote:
>
> In message: [yocto] Help with setting up a PREEMPT_RT image for BeagleBone
> Black #yocto
> on 27/10/2022 [email protected] wrote:
>
> > Hello all,
> >
> > I am new to Yocto and would like to seek assistance for setting up a
> > PREEMPT_RT
> > image for BeagleBone Black.
> >
> > Here is what I have tried so far. First I followed the Yocto Project Quick
> > Build tutorial in the documentation.
> >
> > 1)
> > sudo apt install gawk wget git diffstat unzip texinfo gcc build-essential
> > chrpath socat cpio python3 python3-pip python3-pexpect xz-utils debianutils
> > iputils-ping python3-git python3-jinja2 libegl1-mesa libsdl1.2-dev pylint
> > xterm
> > python3-subunit mesa-common-dev zstd liblz4-tool
> >
> > 2)
> > git clone git://git.yoctoproject.org/poky
> >
> > 3)
> > cd poky
> >
> > 4)
> > git checkout -t origin/langdale -b my-langdale
> >
> > 5)
> > git pull
> >
> > 6)
> > source oe-init-build-env
> >
> > 7) Then I went to poky/build/conf and edited local.conf by uncommenting
> > MACHINE ?= "beaglebone-yocto"
> > and commenting out
> > #MACHINE ??= "qemux86-64"
> > Then I added these two lines at the bottom of the file:
> > PREFERRED_PROVIDER_virtual/kernel = "linux-yocto-rt"
> > COMPATIBLE_MACHINE_beaglebone-yocto = "beaglebone-yocto"
> >
> > 8) Next I ran this command:
> > bitbake core-image-minimal
> >
> > 9) Then I get errors at this point.
> > ERROR: Nothing PROVIDES 'virtual/kernel'
> > linux-yocto-upstream PROVIDES virtual/kernel but was skipped: Set
> > PREFERRED_PROVIDER_virtual/kernel to linux-yocto-upstream to enable it
> > linux-yocto PROVIDES virtual/kernel but was skipped: Set
> > PREFERRED_PROVIDER_virtual/kernel to linux-yocto to enable it
> > linux-yocto-rt PROVIDES virtual/kernel but was skipped: incompatible with
> > machine beaglebone-yocto (not in COMPATIBLE_MACHINE)
> > linux-yocto-dev PROVIDES virtual/kernel but was skipped: Set
> > PREFERRED_PROVIDER_virtual/kernel to linux-yocto-dev to enable it
> > linux-yocto-rt PROVIDES virtual/kernel but was skipped: incompatible with
> > machine beaglebone-yocto (not in COMPATIBLE_MACHINE)
> > linux-yocto-upstream PROVIDES virtual/kernel but was skipped: Set
> > PREFERRED_PROVIDER_virtual/kernel to linux-yocto-upstream to enable it
> > linux-yocto PROVIDES virtual/kernel but was skipped: Set
> > PREFERRED_PROVIDER_virtual/kernel to linux-yocto to enable it
> > linux-yocto-tiny PROVIDES virtual/kernel but was skipped: incompatible with
> > machine beaglebone-yocto (not in COMPATIBLE_MACHINE)
> > linux-dummy PROVIDES virtual/kernel but was skipped:
> > PREFERRED_PROVIDER_virtual
> > /kernel set to linux-yocto-rt, not linux-dummy
> > linux-yocto-tiny PROVIDES virtual/kernel but was skipped: incompatible with
> > machine beaglebone-yocto (not in COMPATIBLE_MACHINE)
> > ERROR: Required build target 'core-image-minimal' has no buildable
> > providers.
> > Missing or unbuildable dependency chain was: ['core-image-minimal',
> > 'virtual/
> > kernel']
> >
> > Summary: There was 1 WARNING message.
> > Summary: There were 2 ERROR messages, returning a non-zero exit code.
> >
> > I've tried a variety of ways and read lots of links but still no luck. Can
> > someone tell me the best way to accomplish my goal?
> > Thank you for any help.
>
> To build a kernel recipe (not just linux-yocto), it must be marked
> as compatible with your machine. The messages you are seeing are
> telling you that, by indicating that the recipes were skipped (since
> they are not compatible) and once they are all skipped you get a failure
> as nothing provides virtual/kernel.
>
> For linux-yocto, you also need a BSP description that the tooling
> uses to create the kernel configuration.
>
> We haven't been testing the beaglebone-yocto reference against -rt,
> so it isn't marked as compatible by default. That being said, it
> can be easily made compatible via a bbappend. Look at the
> meta-yocto-bsp layer, and the bbappends in there. We are adding
> the reference boards as compatible with linux-yocto. A similar
> bbappend would work for linux-yocto-rt, and you'd solve that first
> issue of not having a compatible machine.
>
> For the BSP description, it does happen that we have one in the
> linux-yocto configuration meta-data, so one doesn't need to be
> created. The tools would find that description during the build
> and use it accordingly. The default KBRANCH should aslo be fine
> for the beaglebone-yocto, as we aren't carrying any extra patches
> for the board, so the linux-yocto-rt recipe's default values will
> get the right branch checked out and built.
>
> Whether it builds (it should), boots (it should) or gives you
> appropriate -rt performance (unknown) .. are other questions
> that are to be answered :)
>
> Bruce
>
>
> >
> > Michael
>
> >
> >
> >
>
>
>
>
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