CONFIG_DMA_UNCACHED_8M is not available for thedefaultarchitecture x86.
Result is shown for architecture blackfin
default or selected kernelversion does not have config value CONFIG_DMA_UNCACHED_8M.
Result is shown for kernelversion 6.7-rc3
Enable 8M DMA region
configname: CONFIG_DMA_UNCACHED_8M
Uncached DMA region
└─>Enable 8M DMA region