DDR problem

Dave Ashley linuxbios at xdr.com
Thu Jul 17 18:28:00 CEST 2003


I think this problem is configuration of Rx58 bits 7-5, you have 10/11
bit column address but it is behaving like 9 bit column address.

 From looking at the code for ddr init it looks like cpu address
shifted right by 3 bits is the address going into the chip. So
accessing 0x150 is really like accessing 0x02a on the ddr chips.
Accessing 0x1000 is chip address 0x200 which overflows 9 bits.

I can get this same behaviour with to DDR rams. However when I try to
configure ddram control matching award bios settings, it works better
but fails later during vga init I think. Passes ramtest also.

-Dave


>SDRAM verify:
>00000000:00001000
>00000004:00001004
>00000008:00001008
>0000000c:0000100c
>00000010:00001010
>00000014:00001014
>00000018:00001018
>0000001c:0000101c
>00000020:00001020
>00000024:00001024
>00000028:00001028
>0000002c:0000102c
>00000030:00001030
>00000034:00001034
>00000038:00001038
>0000003c:0000103c
>Too many errors.



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