Chumby 8 Kernel Upgrade: Solving the 100% CPU Usage Mystery

While upgrading the Linux kernel of his Chumby 8 device to version 6.x, the author encountered a persistent 100% CPU usage problem. Through time-reversal debugging, kernel profiling, and a deep dive into the `/proc/stat` file, the root cause was traced to a timing issue in the kernel code that reads the PXA168 hardware timer register, resulting in inaccurate idle time counting. The author fixed this problem and contributed the solution back to the main Linux kernel.