Re: Preempt-rt kernel build for beagleboard


Yu Pan <panyu2000@...>
 

On Thu, Nov 29, 2012 at 1:58 AM, Bruce Ashfield <bruce.ashfield@...> wrote:

Mystery solved. The fragment is picked up properly in the build and
everything is operating as expected.

We had an old commit (that is still required for some configurations)
that disabled preemption for the beagleboard due to SD card boot
issues.

That being said, the entire point of trying out preempt-rt is for the
extra preemption, and without it, why bother. So I moved the preempt
disable to the standard kernel only in this commit:

http://git.yoctoproject.org/cgit/cgit.cgi/yocto-kernel-cache/commit/?id=551c7ad8c46d371c6b135357ed2d388d45af13d8

Once I update the SRCREVs for the meta branch of the linux-yocto-3.4
tree, you'll get the expected preempt settings out of the box:

> grep PREEMPT linux-beagleboard-preempt-rt-build/.config
CONFIG_TINY_PREEMPT_RCU=y
CONFIG_PREEMPT_RCU=y
CONFIG_PREEMPT=y
CONFIG_PREEMPT_RT_BASE=y
# CONFIG_PREEMPT_NONE is not set

# CONFIG_PREEMPT_VOLUNTARY is not set
# CONFIG_PREEMPT__LL is not set
# CONFIG_PREEMPT_RTB is not set
CONFIG_PREEMPT_RT_FULL=y
CONFIG_PREEMPT_COUNT=y
CONFIG_DEBUG_PREEMPT=y
# CONFIG_PREEMPT_TRACER is not set

Thanks a lot for helping Bruce. 

I'm trying to do the modifications to the scc here in the meta branch using  a local bare clone of the linux-yocto-3.4 repository. Still trying to figure out the bitbake patching failures after modifying the SRCREV_meta value to point to my recent most meta commission. Will let you know.

Cheers
Pan Yu

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