2010/7/31 Stefan Reinauer stefan.reinauer@coresystems.de:
On 7/31/10 4:56 PM, Zheng Bao wrote:
The board tht I am working on has 2 process. Each of them has 6 DIMM slots. If you plug 1 dimm into each slot, the SPD address will be, Channel PCB ---------------- P0: DIMMA0 50h DIMMA1 51h DIMMA2 52h DIMMB0 53h DIMMB1 54h DIMMB2 55h P1: DIMMA0 50h DIMMA1 51h DIMMA2 52h DIMMB0 53h DIMMB1 54h DIMMB2 55h If you plug 1 dimm in P0DIMMA0 and the other in P1DIMA0, the SPD address will be 50h and 55h. So I am confused. If we got an active spd 0x50 on the SMBUS, what will it be? It seems that we can not plug more that 8 dimm even if we have 12 slots, correct?
Zheng
There is probably an smbus hub for switching between the P0 and P1 SPD ROMs.
Check out src/mainboard/tyan/s4880/romstage.c for an example of a board with smbus hub.
Another example is in the serengeti_cheetah romstage.c activate_spd_rom().
Marc