Modern high-speed DRAM interfaces are very complex. Their initialization is dependent on the particular memory module in use, and some parameters are even deter

Modern high-speed DRAM interfaces are very complex. Their initialization is dependent on the particular memory module in use, and some parameters are even determined at power-on via training. So there actually are no "sensible defaults" which can be expected to work reliably with all memory modules. The initialization and training routines are far too complex to justify implementing them entirely in hardware, thus the need for software hacks to get things up and running.