Are bits 31:24 and 15:8 of MC_CNTL/MEM_CNTL (0x140) on the RV280 documented? I've noticed that card with 128 MB SDRAM and two channels are set to 2e002e01, and cards with 256 MB SDRAM are set to 32003201. Do the bits describe the memory chips themselves? Is the memory controller initialization process documented?
Are bits 31:24 and 15:8 documented?