So, what went wrong?
Apparently, DDR BUS values reported by FKM are taken from the ddr-bw node taken from /sys/class/devfreq. The formula used is cpubw * 0.065536.
However, in 4.19, the path changed. cpubw -> cpu_cpu_llcc_bw now, but in FKM it was set to cpu_llcc_ddr_bw, which is llccbw on 4.9.
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