SK-AM62B-P1: How to modify driver source code before rebuild RT-LINUX image

Part Number: SK-AM62B-P1

Tool/software:

Hi Teams

In past, I modify driver and rebuild default LINUX image as below step

1.  MACHINE=am62xx-evm bitbake -c cleansstate tisdk-default-image

2.  MACHINE=am62xx-evm bitbake -c cleansstate linux-ti-staging

3.  MACHINE=am62xx-evm bitbake -c menuconfig linux-ti-staging

4.  modify driver(build/arago-tmp-default-glibc/work-shared/am62xx-evm/kernel-source/sound/core/pcm_lib.c)

5.  MACHINE=am62xx-evm bitbake  linux-ti-staging

6.  MACHINE=am62xx-evm bitbake  tisdk-default-image

The driver source code & image can be rebuild and useful.

But if I set to rebuild RT-LINUX, the driver's modify doesn't seem to work

1.  MACHINE=am62xx-evm bitbake -c cleansstate tisdk-default-image

2.  MACHINE=am62xx-evm bitbake -c cleansstate linux-ti-staging

3.  MACHINE=am62xx-evm bitbake -c menuconfig linux-ti-staging

4.  modify driver(build/arago-tmp-default-glibc/work-shared/am62xx-evm/kernel-source/sound/core/pcm_lib.c)

5.  MACHINE=am62xx-evm bitbake  linux-ti-staging

6.  MACHINE=am62xx-evm ARAGO_RT_ENABLE=1  bitbake tisdk-default-image

Did I lose some settings? Or modify the wrong source code?

Thanks