2.6.4. Validating Configuration

You can use the do_kernel_configcheck task to provide configuration validation:

     $ bitbake linux-yocto -c kernel_configcheck -f
                

Running this task produces warnings for when a requested configuration does not appear in the final .config file or when you override a policy configuration in a hardware configuration fragment.

In order to run this task, you must have an existing .config file. See the "Using menuconfig" section for information on how to create a configuration file.

Following is sample output from the do_kernel_configcheck task:

     Loading cache: 100% |########################################################| Time: 0:00:00
     Loaded 1275 entries from dependency cache.
     NOTE: Resolving any missing task queue dependencies

     Build Configuration:
         .
         .
         .

     NOTE: Executing SetScene Tasks
     NOTE: Executing RunQueue Tasks
     WARNING: linux-yocto-4.12.12+gitAUTOINC+eda4d18ce4_16de014967-r0 do_kernel_configcheck:
         [kernel config]: specified values did not make it into the kernel's final configuration:

     ---------- CONFIG_X86_TSC -----------------
     Config: CONFIG_X86_TSC
     From: /home/scottrif/poky/build/tmp/work-shared/qemux86/kernel-source/.kernel-meta/configs/standard/bsp/common-pc/common-pc-cpu.cfg
     Requested value:  CONFIG_X86_TSC=y
     Actual value:


     ---------- CONFIG_X86_BIGSMP -----------------
     Config: CONFIG_X86_BIGSMP
     From: /home/scottrif/poky/build/tmp/work-shared/qemux86/kernel-source/.kernel-meta/configs/standard/cfg/smp.cfg
           /home/scottrif/poky/build/tmp/work-shared/qemux86/kernel-source/.kernel-meta/configs/standard/defconfig
     Requested value:  # CONFIG_X86_BIGSMP is not set
     Actual value:


     ---------- CONFIG_NR_CPUS -----------------
     Config: CONFIG_NR_CPUS
     From: /home/scottrif/poky/build/tmp/work-shared/qemux86/kernel-source/.kernel-meta/configs/standard/cfg/smp.cfg
           /home/scottrif/poky/build/tmp/work-shared/qemux86/kernel-source/.kernel-meta/configs/standard/bsp/common-pc/common-pc.cfg
           /home/scottrif/poky/build/tmp/work-shared/qemux86/kernel-source/.kernel-meta/configs/standard/defconfig
     Requested value:  CONFIG_NR_CPUS=8
     Actual value:     CONFIG_NR_CPUS=1


     ---------- CONFIG_SCHED_SMT -----------------
     Config: CONFIG_SCHED_SMT
     From: /home/scottrif/poky/build/tmp/work-shared/qemux86/kernel-source/.kernel-meta/configs/standard/cfg/smp.cfg
           /home/scottrif/poky/build/tmp/work-shared/qemux86/kernel-source/.kernel-meta/configs/standard/defconfig
     Requested value:  CONFIG_SCHED_SMT=y
     Actual value:



     NOTE: Tasks Summary: Attempted 288 tasks of which 285 didn't need to be rerun and all succeeded.

     Summary: There were 3 WARNING messages shown.
                

Note

The previous output example has artificial line breaks to make it more readable.

The output describes the various problems that you can encounter along with where to find the offending configuration items. You can use the information in the logs to adjust your configuration files and then repeat the do_kernel_configme and do_kernel_configcheck tasks until they produce no warnings.

For more information on how to use the menuconfig tool, see the "Using menuconfig" section.